I was just thinking about this, and was wonder if we are in private or public beta? I just joined, and have no way of knowing. I am kind of curious because I would like the beta badge.
Coffee is currently in public beta. The private beta began on 2015-01-27; the public beta began on 2015-02-09. This is typical of Stack Exchange sites: the private beta period is usually 2-3 weeks long.