A couple of blogs I'm subscribed to are pimping the brand new Yahoo! Pipes which I unfortunately can't seem to access right now. You can read some of the hype in blog posts like Jeremy Zawodny's Yahoo! Pipes: Unlocking the Data Web and Tim O'Reilly's Pipes and Filters for the Internet where it is described as "milestone in the history of the internet". I'd have loved to try out the service giving my interest in mashups and feed syndication but the site seems to be down or is just really, really slow.

As Dave Winer writes in his post Pipes Investigation

I see that Yahoo has a new web app, called Pipes, that looks to me like a feed construction kit. It takes RSS inputs, processes them in ways that are specified by the user, and produces feeds as its output.
...
From a quick persual of the functionality last night and the fact that the server isn't responding right now (5:45AM Pacific), it seems this app uses lots of CPU on the server. 

As someone who works on large scale online services for a living, Yahoo! Pipes seems like a scary proposition. It combines providing a service that is known for causing scale issues due to heavy I/O requirements (i.e. serving RSS feeds) with one that is known for scaling issues due to heavy CPU and I/O requirements (i.e. user-defined queries over rapidly changing data). I suspect that this combination of features makes Yahoo! Pipes resistant to popular caching techniques especially if the screenshot below is any indication of the amount of flexibility [and thus processing power required] that is given to users in creating queries.

Really interesting idea though. I agree with Dave Winer that this is definitely fodder for geeks and not the average Web user. After all, RSS still hasn't crossed the adoption chasm with average Web users let alone an RSS feed remixing service.