1) In general, the database is always the bottleneck. It's easy to throw up more webservers- can't do that with db's.
2) Throw up an ad or two, with the goal of having the ad revenue pay your server costs. This will allow you to not worry about the financial situation while you're fighting fires, so you can defer thinking about investment etc until later.
(now after you have the servers tamed...)
3) Make sure you are incorporated. You probably want to be an S corp or LLC.
4) Look at your metrics and decide whether you have a sustainable property or not. (Look at your retention numbers) Based on the data, decide whether you have
(a) a self-sustaining cash cow, (b) something that can be huge and take over the world, or (c) a fad that will grow and die quickly.
If (b), and you need money to get there, start talking to investors. But don't take money too hastily- it's a long term commitment and you'd better know what you're getting yourself into.
If (c), try to sell it to someone who thinks it's a (b) before it dies.
So you either want to sell as it nears the that peak, or you have to be ready to stick out the trough of sorrow and invest a lot of time into finding a way to grow and monetize it.
So if you have some great vision for how you can turn this into something awesome, super-popular, and monetizable and you want to invest the time in it, you should go for it.
But if not, you're probably going to get some very good offers over the next few days--especially compared to how little time you've invested. If I were you and wasn't totally in love with the site, I'd get out while the offers are good and invest that money into your other businesses. Then when your next site goes viral, you'll just have to wonder how to get it back up ASAP, not how to afford doing so :)
But according to Crunchbase, formspring raised a $10MM series B just over a month ago (well after the decline was obvious). I wouldn't be surprised if some of that went directly into the founders' pockets.
Possibly. And if not there's a good chance that they'll do ok after an exit anyway. But they've already spent a year of their lives doing Formspring fulltime, and they'll probably spend a few more years. So Mark needs to decide whether he wants threewords.me to become a major part of his life for several years. If he does, he should keep it. But if not, now's a much better time to sell than after months of putting it on the back burner and having the viral traffic subside.