This allows you to create your own mashup feed. You can provide up to 6 different RSS feeds and decide how many articles you want in your feed. Run the Pipe, and under More Options, click on "Get as RSS." You will have your own mashup feed that you can import to your RSS reader.
Pipe Web Address: http://pipes.yahoo.com/pipes/pipe.info?_id=PuMT3B3j3BG4_b4uYEsBXw