I got an early peek at this months ago and I loved the concept. Anil has a write up here. From it:
Yahoo’s launched an interesting and innovative new service, Pipes, which lets users with a relatively low degree of technological expertise combine structured sources of web data such as feeds. In this way, it’s possible for non-experts to create new web services for their own use or for public consumption. Pipes combines a remarkably sophisticated development environment with some core social features such as the ability to clone or share the web services you produce. The service is fairly approachable, but somewhat complex once you get just under the surface, and should be moderately successful while radically raising the bar for other tools in its category.
Oh, and Tim’s stoked too.