And of course, coincidence or not... does it really matter? I don't think anyone with a straight face could accuse TechStars or YC of actually stealing ideas at the investor level, but if an enterprising entrepreneur sees a good idea put into action at one, thinks he or she can do it better and pitches it to the other, so what? From a consumer standpoint, competition is good. (Actually, it's good from an entrepreneurial standpoint as well.)

Anyway, I think likely these are coincidence more than anything. A good rule of thumb: If you have a good idea, someone else has it as well. Right now. And they're working on it, too.

Anecdote: My biz partner and I started work on what we think is a great idea beginning of last December almost immediately after a late-night brainstorming session on IM. By mid-January we'd identified two similar competitors that had launched in the past couple of months. By February we found another that seems similar (but is unlaunched). And two weeks ago a fourth competitor came out of nowhere and launched.

All that means is that other people think our idea is good, too. We think that's probably a good sign (and so hope to launch in the next couple of weeks).