Update: ExecTweets is not the only thing Twitter is advertising. You can also see other ads for things like TwitterVision, Tweetie, etc. in the little box that previously only advertised Twitter services. Everything still looks to be at least Twitter-related at this point. And from the sound of it, they’re not making a money off of it.
ExecTweets Provides Revenue To Twitter
Well, Twitter is making more noise by getting Microsoft to spend money with them for a sponsored page called ExecTweets according to Peter Kafka at All Things Digital.