1/ @jetbrains' Space is potentially the @SlackHQ killer among many others. But I have some reservations:
1. Is it #opensource when the self-hosting is released?
2. Are issues stored in yet-another separate DB instead of a standard format in the source code repertory?
1. Sorry, Space is not open source and won't be. 2 & 3. All the issues and chat history, as well as code reviews and other meta information, are stored in the database. You can export it via the API, but we don't put it next to your code in the git repository.