This is cool. Sorry don't have time to do a detailed test drive now, but I see others have done that, and I just wanted to add that YES this is a great concept and something I have been wishing for. Dodgeball was close, Twitter is OK for this but too noisy and not always followed closely enough, but this gets right down to a core use case that is near and dear. One nice thing is that since the use case is narrow, getting updated via SMS would work, at least for people with good SMS quota plans.

Also both the name and the subtitle are great, and I won't be surprised to see them inspire other -able and -onty names shortly.

A money maker? I don't understand how, but you have thought about it way more than me, so maybe you have a way.