I did submit an application but I'm confused now. Did you found VC3 to discuss how to build fun and profitable social media sites or is VC3 the fun and profitable social media site. Because it says on the site that it's free and not for profit?
The community on HN is awesome for getting really nitpicky, but the audience for discussing these sorts of problems is only a small slice of the larger HN audience. I started VC3 as a community formed around a specific purpose (discussing "building meaningful community") specifically to try to build more engaging and valuable discussion, and I personally think that a smaller, closed forum of enthusiastic individuals is a better way to do that than a public general-topic forum.
There's a question in our FAQ [0] that goes into this in even more detail. Look for the header "Why is VC3 its own site?"