Twitter and to a lesser extent Facebook are like ghetto art communities on the verge of gentrification: Hipsters are loving the first-there, build-something-from-scratch feeling, and hungry capitalists are eyeing the goods and trying to figure out how to get in on the action and make a profit. But few companies have figured out how to capitalize on all that coveted word-of-mouth and networking.

Part of the problem lies in the very nature of social networks: People just want to talk with their friends. And part of the problem is that outside of Facebook's stray ads, the two most talked about social networks (Facebook and Twitter) don't really offer businesses clear-cut entry points because they don't yet need to--Twitter, for example, is flush with US$35 million in VC funding--but eventually a sustainable business model will be necessary. Just how that profit will be made and which social networks will reign supreme is a matter of opinion.