Does anyone use Mattermost? I remember thinking it wasn't too bad, and I guess it's open source.
I mentioned them last week and per the comments I got, not really: https://news.ycombinator.com/item?id=46901946
alt Hacker News
I mentioned them last week and per the comments I got, not really: https://news.ycombinator.com/item?id=46901946