It's not too late for a post on #libremonday!
I would like to focus on [#Mattermost](http://mattermost.org/) today which we at our institute use for team collaboration and project management. It is an open source alternative to [Slack](http://slack.com/), but slim and non-distracting.
I would not say that it has become a substitute for email, but for targeted problem solving it works great.
For further reading on Slack and the like in research see e.g. https://www.nature.com/news/how-scientists-use-slack-1.21228