Twitpay has been busy.
Let's say you are a coffee company looking for a way to promote your newest seasonal drink, the Pumpkin Latte. In order to get people talking about your product on Twitter, you could use RT2Get to start a retweet campaign:
The first 1000 people to retweet this message get one free pumpkin latte RT2Get 23212
This could be a pretty powerful way to harness the viral nature of twitter.