Slack — friends first, then the queue
Slack · 2013
Preview release · 8,000 requests on day 1
What they built: request-an-invite page + waves of new teams
What they didThe team used Slack internally first, then talked friends at six to ten other companies into trying it. When the public preview opened, people had to request an invitation.
Why it workedEach new group of testers was bigger than the last, so problems showed up at the size where they mattered — a much larger team, Rdio, used it very differently. The invite queue — 8,000 requests on day one, 15,000 two weeks later — gave them demand they could absorb without breaking.
Copy thisRecruit 5–10 friendly teams before any public beta. Then open a request-an-invite page and let people in in waves.








