Streaks began with a hypothesis about milestones: if we celebrated key days (3, 6, 10), users would be more likely to push toward the next one, driving our core metric of week-over-week food logging. For the first test, I worked with our business intelligence team to source social proof claims like "You're in the top 50% of users!" [LIFT: placeholder].

Frequency

That result opened a bigger question: how far could frequency go? We kept testing more celebration days until we were celebrating every single day from day 2–10. We found [that daily celebration outperformed milestones alone by X% / that we hadn't yet hit a ceiling on "too much"] — placeholder.

Timing

Alongside frequency, we tested timing: celebrating a user the instant they logged food and incremented their streak, versus waiting until they returned to the Today screen. The in-the-moment celebration won, even though it interrupts the user mid-task [LIFT: placeholder]. The principle this surfaced: celebrations are welcome distractions as long as they feel meaningful in the moment they happen.

Copy

With frequency and timing solved, I turned to copy. My hypothesis was that novel, varied copy each day would outperform repetition. But, it didn't. leaderboard-style social proof still won [LIFT: placeholder]. The takeaway reframed how I thought about streak copy going forward: users respond less to novelty than to feeling part of something larger than themselves.

That insight opened a second question: could belonging be built through identity, not just scale? I tested a day-1 streak for returning users (deliberately placed away from registration-day messaging clutter) leaning on identity: "Mary is back!" It won [LIFT: placeholder], confirming that identity-based framing can be as powerful as social proof.

Currently in testing is the inverse case: a day-1 streak for new users leaning on scale rather than identity: "You just joined 2.5 million users logging food today." [Results pending.]