[mugsie]

A selection of reasons I have heard.

- Because self hosted HipChat / IRC / XMPP / is not cool enough.

- Because we are all supposed to use Lync / Skype for Business, but it sucks on OSX / Linux / in general.

- Because we are a small team, and maintaining a chat server is too much for us.

- Because we don't know (or want to know) how Slack works.

- Because shiney, such giffy, such memes.

- Because its free.

- Because my software engineers don't know how to connect to IRC

There is varying levels of good and bad reasons in there. (personally I am still a irrsi / IRC person, but I fully acknowledge I am not in the majority anymore)