Anything like this already exist? If so, what's your experience with it?
A hn user also launched http://www.weekendhacker.net which got a bit of traction at the time.
You have also reminded me of the Startup or Shutup thread someone started in 2012.
https://news.ycombinator.com/item?id=3394844
Some of the discussion is here...
https://groups.google.com/forum/m/#!forum/startup-or-shut-up
I recall the live document linked in the hn thread having activity at the time too but its not working anymore.
It could be a nice idea to let users add topics they are interested in building something for. Then, when someone else have the same interests, send out an email.
For example. I am working on an iOS application about the Thai language. And it would be awesome to find someone else interested in it. But it feels strange to ask about either one in forums related to either one.