Plagger
This seems to be interesting work by the Japanese, similar to Yahoo pipes.
Plagger is a pluggable RSS/Atom feed aggregator written in Perl. Everything is implemented as a small plugin and you can mash them up together to build a new application to handle RSS/Atom feeds. Ray Ozzie said RSS can be Unix Pipe of the Internet and that way Plagger is an Unix shell for Web 2.0
