P2
Interestingly it started out as a more Synchronous Communication tool that Automatic (company making Wordpress) used.
However, compared to Slack, it has far better Information Stability due to it's permalinks and such, making it more of a Asynchronous Communication tool. On their website they say:
Automattic is an office-less, globally distributed company, and P2 is our lifeblood. We built it to give everyone a place to see all of their projects and files, collaborate transparently, and to do it all** without constant distractions**.
Looks like they're trying to develop it into a product eventually at the link above.
See: Remote Companies end up building a Async Communicaiton tools
Backlinks: