Facebook announced it will pay out $2 million to winners of its second fbFund developers' competition. 25 first-round winners will get $25,000 each, and five second-round winners will win $250,000. The money comes as a grant, not an investment, with the only stipulation being that Facebook backers Accel and Peter Thiel's Founders Fund get the right of first refusal for any investment rounds in the future.Last fall, Microsoft paid $240 million for 1.6 percent of Facebook, along with an advertising deal. That wasn't because it was a popular social network, but because the tech press was talking up Facebook as a platform for social applications — a Windows for widgets. Facebook's platform has fallen far short of that promise. The successful apps widgetmakers created in the first year of the platform's existence succeeded through spammy viral tactics, not by being particularly useful or fun for Facebook users. Social-games maker Zynga, for example, makes its games easier to win for users who invite their friends to play. Facebook began changing its platform rules to discourage such tactics in January. This summer, it brought out the stick, suspending popular applications like Top Friends for violations. Now comes the carrot, in the form of the fbFund. To taste Facebook's cash, developers must meet a specific set of criteria from Facebook. We've translated them from PR-speak below. Facebook's criteria: