HN user
Don't start from scratch! That lesson is reiterated over and over.
Start as soon as possible with a minimum viable solution, get community growing, and the software solution will create itself based on real needs.
This was the first idea that popped into my head, but I have not been using it yet. My only worry is that it is still not proven reliable or stood the test of time. Its seems nice and pretty, which is great, but I wouldn't want its growing pains interfering.
A more proven alternative may be simply to use google talk (with history tracking if you want that), google groups, and (gasp) email.