Since Facebook opened its platform to third party applications, some of these widgets have seen growth rates that I have not seen since Hotmail's early days. The viral fuel is all of your friends are notified when you add a new application. Facebook applications are already starting to get commercialized through affiliate links and sponsorships. The trick, in this opt in dynamic, is getting individual Facebook members to elect to add a commercialized widget to their profile. Ever the free thinker, Robert Scoble took this to the logical extreme and blogged about a model where Facebook members are paid to promote commercialized widgets to their friends. Let's just hope that in order to hold off the wave of Spammers who will inevitably jump on this opportunity, Facebook continues to build in strong controls for its members to manage what appears in their newsfeed.