Does building in public actually help you launch, or does it just waste energy?

When we started our first project, we shared every update on social media thinking it would build an instant waitlist. While we got a lot of high-fives and vanity metrics, very few of those followers actually converted into paying users at launch. ​On our next product, we stayed quiet and focused purely on talking to 10 specific target users. The launch was much smaller in terms of buzz, but our initial conversion and customer feedback were 5x better.

​Is public building overhyped for early-stage validation, or were we just doing it wrong?