You probably have seen it on, like, only 48 blogs, but still, I just.have.to link to this! [Did somebody say, 'bandwagon effect'?] Joel Spolsky gets a free mobile phone (and free downloads!) from a phone company that hoped he would write something about it. Write, he certainly did! Check it out.
On the other hand, Richard Dawkins has used a far more effective way of eliciting a positive go-out-and-buy-it call from a certain blogger: use extracts from the said blogger's posts in his recent book!