Steven Weiss suggests that Facebook get out of the advertising business:

As I discussed with Forbes managing editor Bruce Upbin, Facebook's virtual ID can easily be used as a credit card (which we'll call "FacebookCard")—a revolving-credit account, just like your Visa or MasterCard, that's usable anywhere. Facebook would have to spend some of the billions it now has in the bank to set up customer-service operations and credit facilities with banks to launch it, and invest in making Facebook logins more secure; the things every credit-card company has to do in order to operate.