https://www.flowdock.com https://www.flowdock.com , besides all the normal features you mentioned, it has excellent thread support, which is huge! So you can ha

https://www.flowdock.com https://www.flowdock.com , besides all the normal features you mentioned, it has excellent thread support, which is huge! So you can have multiple conversations in the same channel/flow during several days and can just ignore whichever thread isn't for you. We have been using it with a 100% remote team for over 6 years.