What part do you want to be open source? The software that runs the matchup? I think most browsers support WebRTC so that problem is mostly solved. People can use Facetime or Google+ Hangouts for free. So all that's needed is a way to meet people. I suppose pretty much any live chat for pr0n software would do the job as well.

I know there are other companies doing this. My friend is learning English through http://langrich.com which connects students of any age in Japan to people in cheap labor countries that speak English like the Philipeans for example.