Slack ‘Save for Later’ & ‘Huddles’: How to build features for what your users are already doing

TLDR: WATCH THE VIDEO (click above)

If you’re driving product innovation at a company, you have a lot of ways to do it:

✅ Talking to users

✅ Doing market research

✅ A/B testing & iterating

But there’s another way, too, where success is baked in: aligning product development with existing user behaviors. This approach isn't just about listening to what users say; it's about deeply understanding and responding to what they actually do.

Use case 1: 'Save For Later'

Slack users have been marking messages as unread to save them for later. The formal 'Save for Later' feature just lets people do the same thing—but in an easier way.   

Use case 2: 'Huddles'

Users were already finding ways to collaborate in real-time; Slack recognized this and gave them a more structured, efficient way to do it. And a 'Huddle' doesn’t sound like a ‘meeting’; it's a casual, quick, drop-in interaction that resonates with Slack's ethos.

Use case 3:  Peloton’s 'Stacking'

Peloton noticed users were manually combining classes to create longer workouts. The Stacking feature just encourages people to combine classes in a more seamless way. They made it easier to do the thing that people were already doing.

This seems like a ‘duh’ (of course users adopt features built this way!), but consider how long you were trying to bookmark messages before Slack made this easier for you with a feature. Years! Then the question becomes: how can we pay attention to user behaviors and design for them sooner? At Irrational Labs and in the behavioral science world, we have a repeatable format for uncovering these insights. It’s called a behavioral diagnosis. We study what people do—and we build features based on these insights.

3 things I cover in this teardown:

💡 How to align product development with existing user behavior

💡 How to create a mental model for the key behavior you’re trying to achieve while also putting your stamp on it

💡 How to amplify that behavior by exposing users to it who weren’t doing it already

I’m curious: what are some behaviors you’ve adopted in your daily app usage that you wish had a dedicated feature? Share your thoughts—we’ll explore the intersection of user behavior and product design again next time.

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Questions about your product? Email kristen@irrationallabs.com.