American Idol made its contestants get rid of their Facebook, Myspace, Twitter etc. accounts. I get their point. Some people could be blabber mouths and reveal some Idol secrets. But I think their main reason is that contestants with Twitter accounts and TONS of followers could get more votes just based on their twitter accounts.
Oh and FYI, how much are these social networking sites worth?
Facebook: $11.5 billion
Zynga: $2.6 billion
Twitter: $1.4 billion
LinkedIn: $1.3 billion
Linden Labs (Second Life): $383 million