I'm assuming the site you're speaking of is vying.org, from your profile. Why don't you just ask a straight forward question pertaining to the site specifically? You'd get much more tangible advice.
Personally, as a user, if you gave me a 30-day free account, I'd either find a way to game it, or just leave once the free period is over. I get the whole DHH schtick with charging users for a nice service, but free is free, and I don't think many people would pay for a game site, unless something about your site shines far beyond the multitude of other web game sites, if you're referring to vying.org.