If I can give you any advice at all it would be try to create a reason for those people to come back at some time in the future when you've better figured out what to do with this, you're really sitting on something and chances of hitting it out of the park like that twice are slim.
So, to add to your problems a bit I've given you a homepage link on http://ww.com/
Enjoy the extra traffic :)
j.
The problem as I see it is that our 4000 users means nothing. It's a meme, essentially. Registration happens so quickly that our high numbers don't mean much; the fact that we're getting linked all over means a lot, but I see it as more of a "you have to see this" fad among friends than I see it as dedicated users. (We've got a 50% bounce rate and the average stay lasts under two minutes.)
Anything that we add would have to work without ruining the nature of the site. As in: right now the workflow is "take in answers, give link to profile," which is very sticky but creates a path off the site pretty quickly - and removing that removes the stickiness.
I figure the best route to go right now is just to interact with the people we've got talking to us. We have two email addresses, one for photos and one for haiku, and we got way more submissions than I expected for a first-day submissions thing. Those are the people who're actually talking back and forth with us, so I figure they're a good place to start when it comes to expanding. (I'm figuring out now just how to create the gallery for their stuff.)
My money would be on those doing what they were enjoying best being in the majority.