This is nothing new. Companies have paid celebrities to endorse their products for a long time. This is just taking it to a new level, where companies can pay anyone to endorse their product. I see the effectiveness of this strategy to be limiting because the endorsement is not authentic. Obama doesn't recommend blackberry to his friends because he's paid. College kids didn't create facebook accounts for all their friends because Mark cut them a check. It's authentically loving a business that gets people to talk about it. Twitter is a new means of conversation. But you still can't just pay someone to talk about your product. They have to love it first.