By adding a real-time widget showing how many users subscribed in the last week to the SMS step of the popup, we believed this added element of social proof would create urgency and credibility. Encouraging more users to submit their phone numbers and increase opt-in rates for SMS.

An A/B test was conducted across multiple brands to evaluate the performance of including a “last week’s subscribers” widget on the SMS step. Two versions were tested:

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Visitors were randomly assigned to:

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• The control experience with a standard SMS step, or
• The variant featuring subscriber count on the SMS step only.

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We tracked:

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• SMS Conversion Rate – % of popup impressions that resulted in SMS opt-ins

The control outperformed the variant in most cases:

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Only one instance showed a significant lift in SMS opt-ins, while the majority of results favored the control.

Adding a subscriber count widget to the SMS step produced mixed to negative results. While one brand saw a strong lift in SMS conversions, most showed flat or decreased performance. Suggesting that the widget may have distracted rather than reinforced the CTA.

The takeaway: social proof can be powerful, but timing and placement are everything. On conversion-critical steps like SMS opt-ins, the cleaner path often wins. When testing engagement widgets, always validate performance brand-by-brand.