And then there's Diaspora and Identica where you're neither product nor customer...
Spammer pay thousands of dollars for fresh emailing lists, simply because enough uneducated people will get cough in their nets. You think they won't be able to afford $50?
Ultimately, its up to Dalton and his executive skills (is he going to be the CEO?) to build a company's structure and split the fee the smart way (have a decent anti-spam team) to keep the site fun and clean [of spam].
True, that alone might not do it. The $50 paired with a rudimentary reporting system might limit the use of a single account to a small time period in which the ROI wouldn't be worth it.