Yahoo! Pipes: Create mashup of RSS feeds

Yahoo! Pipes is a powerful composition tool to aggregate, manipulate, and mashup content from around the web. Like Unix pipes, simple commands can be combined together to create output that meets your needs. Here’re few popular usage: create custom feed by combining many feeds into one, then sorting, filtering and translating them – geocode your favorite feeds and browse the items on an interactive map. remix your favorite data sources and use the Pipe to power a new application – build custom vertical search pages – consume the output of any Pipe in RSS, JSON, KML, and other formats.

How to Build a Pipe?