The most interesting things to me is that Campfire was around before this and Hipchat before that. It goes to show that execution is everything, Slack has completely crushed it from a feature and integration standpoint and the polish is amazing. We switched from Hipchat and we didn't really have a good reason - it just felt better.
If Campfire was growing $1MM a month I am pretty sure 37signals would now be called Campfire and not Basecamp.
If Campfire was growing $1MM a month I am pretty sure 37signals would now be called Campfire and not Basecamp.