I had the exact same thoughts as thomasbk, although I have to admit that it does sound kind of cool. No way I would pay $2 or even $1 per day for it, though. Roughly $10 per month sounds reasonable.

I think you'd find that assembling all the right data (which is the true product) is way more work than you imagine. Sure, you could probably do it for yourself with a doable amount of work, but to be able to do it for ANYONE is a massive undertaking. And... yeah, you probably don't want to try to build Google Now.