[fChk]

The biggest opportunity  as I think @Mashiro  mentioned in shoutbox not long ago, we need more on topic posts about what people are doing with their vps. The topics like anime, music, and movies keep the forum active but don't do much for search rankings.

This is the most critical point: the forum suffers content-wise. Hosted members don't quite take their end of the bargain seriously (vis-à-vis of their P4V contract).

I think that it's the false idea of 'free VPS' that's the culprit here. The VPS isn't free, it's granted in exchange of an amount of 20 posts. It takes time to make a post and it takes 20 times as much time to make 20. Time is money for most active people. Thus when you sign up for a VPS, you have to find that time to pay for it. It's as simple and straightforward as that.

Now for the post quality. Okay! here we can't expect everyone to comply with that all the time, but we can see a pattern on how much hard they're trying over time. A look at the ratio of Credit_point over total_posts will tell you a lot about that. Simple unmistakable Math.

Without decent content, the best SEO in the world won't do much to trigger a positive outcome; it will bring hordes of spammers as @deanhills pointed out but not the right audience.

My 2 cents!

PS: I also back the proposition of creating a (sub)forum on hosted members' projects.