Originally Posted by Wikipedia

Yahoo! Pipes is a Web application from Yahoo! that provides a GUI-based interface for building applications that aggregate Web feeds and other services, creating Web-based apps from various sources, and publishing those apps. The site works by letting users "pipe" information from different sources and then set up rules for how that content should be modified (e.g. filtering). A typical example is New York Times thru Flickr, a pipe which takes the New York Times RSS feed and adds a photo from Flickr based on the keywords of each item. The site is currently in beta.