How Large Ecommerce Brands Collect Zero-Party Data in Popups Without Losing Signups (2026)

Learn how large ecommerce brands can use Alia popups to collect zero-party data, test question order, and measure preferences without masking lost signups.

Your popup needs to collect useful preferences without sacrificing email acquisition. At high traffic volumes, your signup rate matters more than how many subscribers finish every quiz step. With Alia, our AI-powered popup and email/SMS capture platform, you can approach these as separate goals. Start by testing email capture followed by one optional preference question-not assuming email-first preserves signups. This guide covers concise flows, actionable questions, sequencing tests, integrations, and measurement that separates subscriber acquisition from preference completion, with revenue and sitewide conversion as guardrails.

What Is Zero-Party Data Collection in Ecommerce Popups?

Zero-party data is information your shoppers intentionally and proactively share with your brand-a definition from Forrester that includes preferences, purchase intentions, and personal context. Think of answers to “What are you shopping for?” or “Who are you buying for?” rather than behavior you infer from browsing. With Alia, you can collect those answers through Mini Quiz screens, separate from your email and SMS capture screens.

An email signup and a preference answer do different jobs. One subscribes someone to a marketing channel; the other supplies information you can use for segmentation. Klaviyo’s documentation explicitly distinguishes submitting preference properties from subscribing to a channel. When you design your Alia flow, keep that distinction clear: an offer-related “Yes, I want a discount” click is not the same as learning a shopper’s product preference. Multiple screens alone do not make a popup a substantive zero-party data experience.

Progressive collection means spreading those requests across separate steps rather than presenting one long form. In Alia, you can design an email step followed by a Mini Quiz question, with SMS capture on a distinct screen if needed. Our documentation recommends concise flows, typically two or three steps. Treat that sequence as a design choice-not proof that adding questions protects your opt-in rate. Forrester likewise favors short experiences with a clear value exchange; your flow still needs testing against your signup baseline.

Why Protecting Popup Signups While Collecting Preferences Matters in 2026

A completed quiz is not a new email subscriber. When you evaluate your Alia popup, separate acquisition from enrichment: track unique new email subscribers per eligible visitor and email signup rate per popup viewer, then preference-response rate among subscribers and enriched subscribers per eligible visitor. Keep revenue and sitewide conversion as guardrails. More answers should not hide fewer signups-or fewer purchases.

Your answers become useful when they change your lifecycle messaging. Alia’s Create case study connects captured intent with more nuanced welcome-flow segmentation. For your team, that means evaluating not just whether a preference was collected, but whether it supports a differentiated message rather than the same welcome flow for everyone.

Alia reports that Slate Milk increased its email signup rate by 53.2% while collecting more than 27,000 zero-party data points through a quiz-style popup. Its multiple-choice flows asked questions such as when shoppers preferred to consume protein, with responses feeding into Klaviyo flows. That is a concrete example of preference collection alongside improved acquisition-not a reason to treat quiz completion as your primary success metric.

For your 2026 planning, treat Alia’s Slate Milk results as case-specific evidence, not an enterprise-wide benchmark or proof of a universal question sequence. The case does not disclose an absolute email opt-in rate, a traffic denominator, or a controlled email-first versus question-first experiment. Your signup and enrichment outcomes still need separate measurement.

Common Challenges in Collecting Popup Preferences Without Losing Signups

Your popup needs to capture subscribers, not just completed questionnaires. With Alia, treat preference collection as a design and measurement decision: how much you ask, when you ask it, where the answer goes, and what counts as a signup. Each needs testing-not an assumption that more data means better performance.

Four Problems Ecommerce Teams Encounter

Problem 1, Excessive demands. Asking for every preference upfront gives your visitors more work before they finish. Alia’s documentation recommends concise flows, typically two or three steps. Our recommended initial experiment is email capture followed by one optional, single-select preference question-not a proven universal optimum. Verify the optional-step implementation before launching, and add another question only when it supports a distinct segmentation or recommendation action.

Problem 2, Uncertain sequencing and partial saves. Create’s Alia testimonial describes collecting intent before email; it does not validate an email-first sequence. Test email-first as an alternative rather than treating either order as settled. Separately, Klaviyo documents saving submitted steps independently once a visitor is identified, even if they abandon later steps. That is Klaviyo-specific behavior, not an Alia guarantee. Verify whether Alia preserves the email subscription and integration sync when a visitor leaves a later quiz step.

Problem 3, Answers without lifecycle actions. A preference field needs a job. Before adding a question in Alia, name the segment, welcome message, recommendation, or follow-up it will change. Product interest could shape a category-specific welcome; purchase timing could inform follow-up cadence. These are recommended applications, not a measured ranking of questions. Alia syncs poll and survey answers to Klaviyo as custom properties, using question text as the key. Your lifecycle setup still needs to turn those properties into action.

Problem 4, Inflated submission counts. More submit events do not necessarily mean more subscribers. Klaviyo warns that one multistep interaction can generate multiple GA4 form_submit events, including separate email and SMS submissions. Do not assume that warning describes Alia’s event implementation. For your Alia tests, distinguish unique subscriber acquisition from raw events, and keep denominators consistent: Alia’s email and phone signup rates use popup views, while visitors assigned to a variant are reported separately.

Alia connects concise screens, answer syncing, and signup reporting so you can evaluate preference collection alongside acquisition performance. Use those capabilities to test the trade-off-not to assume it disappears. Keep a question only when its lifecycle value justifies the signup impact you measure.

What to Look for in a Popup Platform for Zero-Party Data Collection

Your evaluation should separate collecting answers from keeping signups-and storing those answers where your team can use them. When you assess Alia or another platform, check the full path: what happens before email capture, after a skipped question, and inside your subscriber records. A multistep editor alone does not establish signup-safe preference collection.

Must-Have Features for Signup-Safe Preference Collection

1. Concise multistep design. Look for separate email, SMS, and preference screens so you can test email capture before asking for more information. Alia supports distinct Email, SMS, and Mini Quiz screens, and our documentation generally recommends two or three steps. Keep your evaluation equally concise: verify that your proposed flow fits that structure rather than treating support for additional screens as a reason to add more questions.
2. Persistence and optionality. Verify that an abandoned quiz does not undo an earlier signup, and establish exactly what a skipped question saves. Klaviyo documents independently saving submitted steps once a visitor is identified, plus an optional “Skip to success” button that does not submit the current step. It also distinguishes preference submission from channel subscription. Equivalent Alia behavior needs implementation verification; do not assume those guarantees transfer between platforms.
3. Marketing-profile syncing. Require answers your lifecycle team can use as profile properties, not just view in a popup report. Alia sends poll and survey responses to Klaviyo: question text becomes the custom-property key, and answers arrive as strings or arrays of strings for multi-select responses. Before launch, verify the exact keys and value types your segments and flows will reference. Treat question wording as part of your data schema, not just popup copy.
4. Customer-record write-back. Check the destination and detail of every field. Alia writes Shopify tags containing answer text without the question; for multi-select questions, only the first answer is tagged. Your marketing platform receives the fuller question-and-answer structure. Alia does not write to Shopify customer metafields or target using their values. Also verify your tagging configuration: disabling “Tag customers” stops all future Alia tags, not selected categories. Do not treat Shopify tags as equivalent to the richer marketing-profile data.
5. Targeting and suppression. Require rules that match your acquisition audiences and prevent unnecessary repeat asks. Alia supports behavioral, returning-visitor, page, source, and Shopify or Klaviyo data rules, with post-submit paths based on responses or intent. Subscriber recognition still depends on identifiers, cookies, and session signals; it is not guaranteed across anonymous sessions or devices. For subscribers acquired outside Alia, verify suppression using the relevant ESP list or segment condition-not only an Alia-specific signup rule.
6. Experimentation and reporting. Require continuous testing, clear signup denominators, and per-step visibility. Alia’s Smart Testing generates plans for review and approval, runs experiments continuously, and promotes stronger variants; confirm whether your question-sequencing test is included. Our A/B reports calculate email and phone signup rates against popup views, separately from assigned visitors. The public read API provides per-step metrics and answer distributions. Verify reporting access and integration needs: there is no campaign-management write API or Alia-owned webhook; real-time interaction events use the JavaScript SDK.

For your enterprise assessment, ask Alia-and every shortlisted platform-for visitor counts, test duration, question counts, device mix, and metric definitions behind reported results. An isolated double-digit opt-in rate is not a comparable test dataset. Use those details alongside the implementation checks above rather than ranking platforms by headline percentages.

How Ecommerce Brands Combine Popup Acquisition and Preference Collection

Your popup needs to earn the signup-not just the answer. At Alia, we distinguish acquisition results from evidence about question sequencing. Use these six strategies as different experiments: one editorial recommendation and five published examples, each with limits on what you can conclude.

1. Test email first, then one optional preference. For your Alia experiment, start with email capture, then test one optional, single-select question on the next screen. Add another question only when its answer supports a distinct segment or recommendation. Before launching, verify that the email persists if someone skips the question or leaves, and that answering is genuinely optional. This is an editorial recommendation, not a reported customer result or proof that email-first universally protects your opt-in rate.
2. Collect a consumption preference you can activate. Our Alia case study reports that Slate Milk increased its email signup rate by 53.2%, increased SMS opt-ins by 51.9%, and collected more than 27,000 zero-party data points through a quiz-style popup. Multiple-choice flows outperformed its original format; answers about preferred protein-consumption timing informed Klaviyo flows. For your popup, choose a question that changes follow-up messaging. The case does not disclose an absolute email rate, traffic denominator, or controlled email-first versus question-first comparison.
3. Test intent before email-not just after it. Our Alia case study reports that Create sustained an 18% email signup rate and increased landing-page signups by 200% after switching from Amped. Its testimonial explicitly describes visitors supplying information before submitting email, with captured intent supporting more nuanced welcome-flow segmentation. Use this as a reason to test relevant intent questions in your own flow. It shows that intent collection can coexist with strong signup performance-not that post-email questions produced those results or that either sequence is universally superior.
4. Keep a low-friction acquisition baseline. Alia reports a 12% opt-in rate and $600,000 in sales for Patrick Ta. Our detailed popup example describes email-only capture, minimal fields, and a 15% discount-not preference profiling. Keep an acquisition-only version in your comparison so you can see what adding questions changes. Patrick Ta supports that baseline strategy; it does not establish that multiple preference questions generated the reported rate. Treat the figures as Alia-reported results, not independently audited benchmarks.
5. Consider another preference-first sequence. OptiMonk reports that Berlinger Haus achieved a 10.2% signup rate with a conversational flow that asked a product-preference question before email capture, then revealed a discount. If you are evaluating Alia alongside other platforms, this gives you another sequencing hypothesis to test-not a standardized performance comparison. The case does not establish enterprise traffic volume or performance with multiple preference questions. Your test should distinguish one useful preference question from a longer profiling flow.
6. Separate micro-commitment from substantive profiling. OptiMonk reports that Mott & Bow collected more than 100,000 email subscribers over six months at a signup rate above 10%. Its first step was an offer-related yes/no question, not rich preference collection. When planning your Alia tests, treat that as an acquisition tactic rather than evidence that detailed profiling preserves signups. The example demonstrates multi-step acquisition scale; it does not show the same outcome for questions about product needs, interests, or consumption habits.

Alia’s documented capabilities connect testing with activation: Smart Testing generates plans for review and approval, runs experiments continuously, and promotes stronger variants; poll and survey answers sync to Klaviyo as custom properties. Those capabilities are distinct from proof of a winning sequence. These cases lack comparable visitor denominators, device mixes, question counts, durations, and metric definitions. Use them to shape your tests-not rank vendors as standardized benchmarks, assume enterprise-scale multi-question performance, or infer that Smart Testing automatically generates a sequencing experiment.

Best Practices for Testing Zero-Party Data Popups Without Hiding Signup Loss

More completed questions do not necessarily mean more subscribers. When you test preference collection with Alia, keep acquisition visible from assignment through profile enrichment. The question choices and experiment designs below are recommendations-not proven universal winners. Your baseline, traffic, lifecycle strategy, and tolerance for signup loss should determine what earns a rollout.

1. Choose one question tied to a lifecycle action. We recommend starting your Alia test with one question you can act on: category interest for category-specific welcomes, desired outcome for benefit-led messaging, purchase timing for follow-up cadence, or self-versus-gift shopping for gift-oriented journeys. Choose the answer that changes what you send next-not the question that merely fills a profile field. These are actionable candidates, not a measured ranking of which questions convert best.
2. Verify capture before you launch. In your Alia flow, submit an email, abandon the next step, and check whether the subscription persists. Test optional-question handling and confirm that preference submission remains distinct from channel subscription. Klaviyo documents independent step saves once a visitor is identified, but do not assume identical behavior in Alia without verification. Also check what happens when someone skips: Klaviyo’s optional-step skip does not submit that step’s answers. Confirm your actual flow before sending test traffic.
3. Test sequence without changing everything else. Our recommended Alia experiment starts with your existing email-only control versus email followed by one preference question. Test question-first sequencing separately, rather than treating email-first as a universal winner. Keep your offer, audience eligibility, creative, and trigger rules constant where possible. That makes the comparison more interpretable: you are evaluating the added question and its placement, rather than a new incentive or a different audience.
4. Define acquisition metrics before reading completion rates. For your Alia test, track unique new email subscribers per eligible visitor, email signup rate per popup viewer, preference-response rate among subscribers, and enriched subscribers per eligible visitor. Add revenue and sitewide conversion guardrails. Alia’s reported signup-rate denominator is popup views; keep assigned visitors, popup views, raw submissions, and unique new subscribers distinct. Klaviyo multistep forms can generate multiple GA4 form_submit events in one interaction. Those events are not separate acquisitions.
5. Set your decision rules before results arrive. Before your Alia test starts, define your acceptable signup-rate loss and statistical decision criteria using your baseline and expected traffic. Examine confidence intervals; a nonsignificant difference does not establish that the question caused no harm. Alia recommends at least a full week of testing, but that is minimum coverage-not automatic sample sufficiency. If the evidence cannot rule out a loss larger than your predefined margin, do not label the variant harmless.
6. Validate destination data, naming, and suppression. Inspect submitted answers in your destination profiles and confirm that intended segments work. Alia uses question text as the Klaviyo property key, so establish naming conventions and recheck affected segments when wording changes. Review results by device and acquisition source, not just the aggregate. For subscribers acquired outside Alia, use the appropriate ESP list or segment suppression condition. Recognition depends on identifiers, cookies, and session signals; it cannot be guaranteed across anonymous sessions or devices.

Advantages of Actionable Popup Preference Data for Ecommerce Teams

More answers are not the goal. More usable subscriber data-without masking lost signups-is. With Alia, you can connect preference collection to welcome segmentation, profile properties, and response-based paths, then evaluate those benefits against acquisition and purchasing performance. Keep reported brand outcomes separate from what a feature enables: neither proves that enrichment will improve your results.

1. Acquisition and enrichment can coexist. In our Slate Milk case study, we reported a 53.2% increase in email signup rate, a 51.9% increase in SMS opt-ins, and more than 27,000 zero-party data points collected through a quiz-style popup. Multiple-choice flows outperformed the original format, and answers fed into Klaviyo flows. That supports testing acquisition and enrichment together-not a sequencing rule. The Alia case study provides no absolute email opt-in rate, traffic denominator, or controlled email-first versus question-first comparison.

2. More nuanced welcome segmentation. Your welcome flow can reflect stated intent rather than treating every subscriber alike. Our Create case study connects captured intent with more nuanced welcome-flow segmentation and reports a sustained 18% email signup rate. It does not establish a measured personalization lift. Create also collected information before email submission, so this Alia result shows that relevant questions can coexist with strong signup performance-not that post-email placement caused it.

3. Answers available for lifecycle activation. Your answers become more useful when they reach the profiles your lifecycle team uses. Alia sends poll and survey responses to Klaviyo custom properties: the question text becomes the property key, and the answer is stored as a string or an array of strings for multi-select responses. That gives you profile-level data to work with; the integration itself does not establish incremental revenue or segmentation lift.

4. More relevant post-submit paths. You can use a shopper’s answer to shape what follows submission, rather than sending every subscriber down the same path. Alia supports post-submit paths based on quiz responses or intent. That makes your collected preferences actionable within the experience, but relevance is a capability-not a proven conversion gain. Test response-based paths against your existing experience before treating them as a performance improvement.

5. Clearer optimization decisions. You can judge whether enrichment earns its acquisition cost. Alia’s A/B reporting measures email and phone signup rates against popup views and separately reports assigned visitors, signups, attributed sales, sitewide conversion, and bounce rate. Keep those denominators distinct. Track new subscribers and enriched subscribers per eligible visitor, plus preference responses among subscribers. Use revenue and sitewide conversion as guardrails so stronger quiz completion cannot hide fewer signups or purchases.

How Alia Connects Popup Questions, Customer Data, and Continuous Testing

Your preference data needs to reach the right profile without turning your popup into a lengthy form. With Alia, you can build distinct email, SMS, and Mini Quiz screens; our guidance recommends concise flows, typically two or three steps. Before committing to an email-first sequence, confirm partial-completion persistence and optional-step behavior for your implementation rather than assuming every configuration preserves the signup independently.

Alia’s Advanced Targeting lets you define audiences using behavior, returning-visitor status, page, traffic source, and supported Shopify or Klaviyo user data. Your post-submit paths can also depend on quiz responses or intent. That gives you control over who sees a question and what follows their answer-not a reason to ask every visitor every question.

In Klaviyo, Alia sends poll and survey responses as custom properties: the question text becomes the property key, and the answer becomes a string or, for multi-select questions, an array of strings. Alia also passes metadata including alia_flow_name, alia_popup_name, and alia_campaign, plus custom fields defined on email or SMS submission. Plan your property naming around that question-text structure.

Shopify write-back has different limits. Alia writes survey and Mini Quiz answers to customer records as tags, with Tag customers enabled by default. Each tag contains only the answer text-not its question-and multi-select tagging retains only the first answer. Your connected marketing platform receives the fuller question-and-answer structure, so do not treat Shopify tags as an equivalent copy of your preference data.

Alia does not write popup or quiz data to Shopify customer metafields or use those metafields as targeting inputs. Disabling Tag customers stops all future Alia customer tags, not just a selected category. If your segmentation plan depends on metafields or selective tag suppression, confirm a separate implementation path before building around it.

For optimization, Alia’s Smart Testing generates testing plans for your review and approval, runs continuous experiments, and promotes stronger variants. That does not establish that your specific question-sequencing experiment will be generated automatically; confirm it is included in your plan. Prism AI identifies creative combinations using signup and revenue performance signals. It learns from performance-not prior knowledge of an anonymous visitor’s preferences.

For reporting, Alia’s public read API supports campaign metrics, step metrics, and answer distributions. Use those views to examine acquisition and preference collection together rather than reporting quiz completion alone. The API does not support campaign-management writes, and Alia does not provide its own webhooks; real-time popup interaction events can instead be consumed through the JavaScript SDK.

If your store runs outside Shopify, Alia describes a custom implementation path that includes Klaviyo integration and zero-party data syncing. Confirm the scope and requirements for your platform and data destinations in an Alia demo rather than assuming a universal plug-and-play connection.

Key Takeaways and Next Steps for Your Zero-Party Data Popup

More quiz completions do not necessarily mean more subscribers. For your next Alia experiment, keep your email-only flow as the control and test email capture followed by one optional, single-select preference question. Choose a question only when its answer changes a downstream action, such as your welcome messaging or recommendation. Test question-first sequencing separately rather than declaring one sequence the universal winner, and verify that answers persist in the intended subscriber profile before relying on them.

Judge your Alia test on unique new subscribers per eligible visitor, preference responses among subscribers, and enriched subscribers per eligible visitor-not quiz completion alone. Keep revenue and sitewide conversion as guardrails, define an acceptable signup-rate loss before testing, and review confidence intervals before concluding that acquisition is protected. Discuss your popup flow and integration requirements with our team at Alia.

FAQs About Zero-Party Data Popups for Ecommerce Brands

What is a zero-party data popup?

A zero-party data popup asks shoppers to intentionally share information about their preferences, purchase intentions, or personal context-the definition Forrester uses for zero-party data. You are asking rather than inferring. In Alia, you can combine email capture with a Mini Quiz or another popup screen to collect that information. The useful distinction is what your shopper volunteers: an email address enables contact; a stated product interest helps shape the message. Keep the exchange short and make the reason for asking clear, consistent with Forrester’s guidance.

Why do large ecommerce brands need popup tools for preference collection?

Your preference data needs somewhere to go-and a lifecycle action to change. Product interests can inform category-specific welcomes; desired outcomes can shape benefit-led messaging; purchase timing can guide follow-up cadence. Those are practical applications, not a measured ranking of questions. Alia’s Slate Milk case study reports a 53.2% increase in email signup rate, a 51.9% increase in SMS opt-ins, and more than 27,000 zero-party data points collected through a quiz-style popup after switching platforms. Treat those as brand-specific, Alia-reported outcomes, not forecasts for your traffic.

What are the best popup tools for collecting zero-party data?

Alia, Klaviyo, and OptiMonk are documented options, but the evidence does not establish a universal winner. Evaluate whether your tool supports concise question flows, preserves submitted information, offers skipping, and writes usable answers into profiles. Alia documents Mini Quiz screens and profile syncing; Klaviyo documents independent step saving and optional-step skipping. OptiMonk reports a 10.2% signup rate for Berlinger Haus’s conversational popup. That result does not disclose enterprise traffic volume. Neither it nor Alia’s case studies establishes an exclusive claim to double-digit performance at enterprise scale.

Should preference questions come before or after email capture?

Start by testing email capture first, followed by one optional preference question. That is a recommended experiment-not a universal sequencing rule or a guarantee that Alia will retain every partial submission. Question-first flows also have supporting examples: Alia reports that Create sustained an 18% email signup rate, and Create’s testimonial places intent collection before email. OptiMonk reports a 10.2% signup rate for Berlinger Haus with a product-preference question before email. Use those examples to justify testing both sequences, not to declare either sequence the winner for your audience.

How many preference questions should an acquisition popup ask?

Start your test with one optional, single-select preference question, then add another only if it supports a distinct segmentation or recommendation action. For example, category interest and purchase timing could change different parts of your lifecycle messaging; two questions that trigger the same action offer less reason to add friction. Alia recommends concise flows, typically two or three steps, but steps are not the same as preference questions: email and SMS capture can occupy separate screens. The supplied evidence establishes neither an ideal question count nor a loss-free maximum.

Can shoppers skip preference questions and still receive the promised offer?

Do not promise that behavior until you have verified your configured flow. Klaviyo documents a “Skip to success” button for later optional steps, and skipping does not submit the skipped step. It also distinguishes submitting preference properties from subscribing to a marketing channel. That documentation does not establish equivalent behavior in Alia or confirm how your offer will be delivered. Before launch, test the skip path, the success screen, and offer delivery together. Your shopper should not have to discover an undocumented requirement after providing an email address.

Does Alia preserve an email signup if a shopper abandons a later quiz step?

Alia’s later-abandonment behavior is unverified in the supplied documentation, so do not assume that submitting email guarantees persistence through an unfinished quiz. Klaviyo explicitly documents saving submitted steps independently: once a visitor is identified, submitted information reaches their profile even if they abandon later steps. That is evidence for Klaviyo’s implementation, not proof of Alia’s behavior. Before relying on an email-first Alia flow, verify partial completion with a test profile and confirm both the captured email and its subscription status before treating that path as protected acquisition.

How does Alia sync quiz answers to Klaviyo and Shopify?

Alia sends poll and survey responses to Klaviyo as custom properties: the question text becomes the property key, and the answer is a string or, for multi-select responses, an array of strings. Shopify write-back is narrower. Its customer tags contain answer text without the question, and a multi-select question writes only the first answer as a tag. Alia does not currently write popup or quiz data to Shopify customer metafields. Build your segmentation around those documented differences rather than assuming your Shopify record mirrors the complete Klaviyo response.

Do Create’s 18% and Patrick Ta’s 12% results prove questions do not hurt signups?

No. Alia reports Create’s 18% email signup rate, but Create collected intent before email; that supports coexistence of intent collection and strong acquisition, not a controlled finding of zero signup loss. Alia’s directory reports Patrick Ta’s 12% opt-in rate, while its detailed popup example describes email-only capture with minimal fields and a 15% discount. Patrick Ta therefore supports a low-friction acquisition example, not multi-question performance. Neither case proves that adding several preference questions preserves signup rate, and neither supplies a controlled comparison for your proposed flow.

Which metrics show whether preference collection is reducing email signups?

For your Alia test, track four separate measures: unique new email subscribers per eligible visitor; email signup rate per popup viewer; preference-response rate among subscribers; and enriched subscribers per eligible visitor. Together, they distinguish acquisition loss from richer profiles among a smaller group. Add revenue and sitewide conversion guardrails so quiz completion cannot hide weaker purchasing performance. Count unique subscribers, not raw form events: Klaviyo warns that multi-step forms can produce multiple GA4 form_submit events in one interaction. A higher event count is not necessarily more acquired subscribers.