It's truly just... insane. There's not a better word for it than that. My tweets are a wealth of data about things I care about. There are so many ways to sell truly useful ads against that – you have to be off your nut not to take this approach. Real-time ads that solve your problems without you doing anything more than gabbing away could make Google look like a two-bit lemonade stand.

"Fuck, I hate AT&T. Worst cell phone service ever."

"Join Verizon today! Get $100 credit when you switch from AT&T."

"... Go on."

edit: And assuming you use Twitter mostly for passive consumption, there's still useful to be derived from your stream. "Boy, this guy sure follows a lot of people from Portland, let's show him Moe's Bike shop ads."