i guess the niche focus of viral marketing with this piece is the "exclusive" characteristics about knowing about content because you're a fan with "special access" or "knowledgeable access" and how long that lasts before it reaches the general public.
also, sweet fuckin' avatar!
And I completely agree with you. I participated in the Thursday / Google Earth hunt as well as a few others over the years. I have also previously worked for Streetwise, Fanscape, and a few others running street team campaigns. It's a fine line of fan interaction / getting everyone involved and breaking fan trust. If the game doesn't have a great pay off, that is a huge let down and it will affect fans' emotions towards album, video, announcement, etc.