Yahoo Pipes let you take RSS feeds (which 99% of people know nothing about), manipulate them with drag-n-drop pseudo-code (which the other 1% finds insulting), and create a new RSS feed slightly different from the original. The limited options available do an excellent job of suggesting interesting things you could do with Yahoo Pipes, and then promptly denying you the ability.
All the same, in a year or so, this tool will be awesome. The next revolution in the Internet is getting more elements on more pages machine readable. That's what RSS does. It lets the computer tell where things are on a page, so you can write nifty programs to have it give you just the headlines, or just the fourth word of the fifth sentence of every article mentioning "Bush" and "dogs".
In the RSS'ifying of the web, we only need a few tools: the ability to generate threads from periodic content without the original author's involvement is key (scraping, already somewhat available). The other tool is the ability to use basic programming structures to reconfigure and combine the data on the fly. That's exactly what Pipes does, and it tries to do it in a way that is accessible to nonprogrammers, so we can all start mixing up the web however we want, as if we were at the great Mongolian Barbecue of All Human Knowledge.
This project from Yahoo gets 4 out of 5 Googles for being forward thinking, and 1 out of 5 Googles for releasing it as a beta project when it's not actually finished at all. I would also like to praise Google for letting Yahoo do this one, we know they were really behind it, but it's nice to let somebody else enter the spotlight for a bit.
Here's my contribution to the world of Pipes, a mashup of threads from some comics I read.