Last week I speculated that the new Twitter’s native Retweet feature was about search, but it looks like maybe I was wrong; it a may be all about advertising, with search playing a supporting role. Robert Scoble says that at today’s TechCrunch Real Time Crunchup, Dick Costolo – Twitter’s COO, said that Twitter will introduce an advertising model. Scoble speculates that this will be done through metadata. He believes the metadata would be revealed when you mouse over a given tweet. I think that the metadata will be used to instantly generate an advertisement and it will be the ad that is revealed when you mouse over the tweet not the metadata.