I would much rather have $25,000,000 a month in real cash, than having other people give me money and have part of my company. Facebook is unlike Twitter. There are a bunch of Twitter clones out there, and Twitter is fairly easy to copy. If Twitter started charging for its services, 99% of the users would migrate somewhere else. I think Facebook has a powerful enough application that other companies couldn't touch it for years, and people would pay for it.