I've had experience of putting what I'm trying to do on Twitter and having a company send me a message offering their service. I'm not sure if it was a bot or not.

It occurred to me that maybe in a few years time we won't be googling for stuff by rather just "asking twitter" and automated bots/crawlers will respond based on where I am, what I asked for and details from my profile.

If twitter could bake in some kind of spam prevention (or reputation system?) it might just work.