http://venturebeat.com/2015/06/24/slack-now-has-1-1m-daily-active-users-300k-paid-seats-25m-in-annual-recurring-revenue/
What is Slack? Should your nonprofit consider using it?  If you have questions about whether or not Slack is a good fit for your organization, we would love to hear from you.
There are a variety of collaboration tools coming onto the market at the moment and we are keeping a close eye on all of them.