Yahoo! Pipes

I messed around a bit with Yahoo! Pipes a few days ago, and it seems like a very cool tool (if a bit hard to use). I made a pipe for my brother's columns in the Stanford Daily, and it works nicely. I also recommend this Freakonomics pipe that only includes Levitt's posts from the blog. There are pipes that do all kinds of crazy mashups, but even the basic filtering functionality is quite useful.