I sent this message to my team at Blinkfire Analytics (in Slack) because I really think it's been a great tool given we are working in a highly distributed environment, and I am travelling from office to office much of the time.
Communication - In a distributed environment like we have and will continue to have, it's super important to over communicate what you are working on, what you are having trouble with, and what you have accomplished on a daily basis.Many times, I get a DM from a team member, and I ask them to switch to the public channel. Most of the time, the team benefits from seeing these private conversations turned public.
Slack is the best groupware tool I've used in my career, and I love that the team has found creative ways to use it and communicate ( Great profile of Stewart, here: http://www.wired.com/2014/08/the-most-fascinating-profile-youll-ever-read-about-a-guy-and-his-boring-startup/ ) - but I think the key to making it work is that 99% of the conversations have to be public. In fact, if i can figure out how to turn off DMs in it, I'm thinking hard about it. Really, the only conversations that should be private are HR and in some cases, corporate finance related. If you have to ask me or anyone else a question that isn't HR related, you should do it in most relevant public channel so we can all learn from the answers and know what's going on.
Interestingly, we haven't had to pay for Slack yet, and it made me question their "premium" vectors of charging not for the number of users, but for data archival and the number of connected services, but after using it for a few months, I now think it's genius. I also know they will have us as a paying customer really soon.