[ricardobeat]

He might have if he trademarked it. A logo being simple doesn't mean it can be copied at will (e.g. Apple, McDonalds, Nike, Mercedes).

Point is, as wmeredith pointed out, he is well known among web designers/developers, created Svbtle (a competing blogging platform), and has been using that as his personal logo for as long as I can remember, maybe half a decade.