As a side note, other than the lack of members, what makes your site stand apart from hacker news and proggit?
The lack of members is the biggest feature. The odds of it turning into the next Reddit/Digg are much lower than the odds of that happening here. :)
Seriously, the idea stemmed from the YC meetup last week. PG said that the YC interviews aren't like interviews at all, they just "Do YC". If the team and YC seem to click, then they get accepted. I think the same thing applies for finding good cofounders--you just start something and see if the chemistry among the team clicks. I've started projects with friends and complete strangers before, and whether or not I knew them before the project isn't correlated with how well we worked together. There are a few people I met the day of starting a joint project who I'd love to start another company with.
That's what I hope this site could do: not just bring hackers together to discuss startups, but bring them together to launch things and find new cofounders.
I think there are a lot of people on HN that would be great to work with, and the best way to find them would be to just start projects. I currently am lucky enough to have a few hours free each day, but unlucky that I'm far from the Valley(I've got family commitments that have been keeping me in Southern MA all summer). When I get to the valley, I think it will be easier to find co-founders, but until then it's not that easy.