Hey, this is cool: Yahoo Pipes. It’s a free tool for playing with RSS feeds.

I used it to create a politics only RSS feed for a Norwegian election blog aggregator, (for some reason they’re not interested in 70 year old movies..) It reads my regular RSS feed, filters it on the category, and outputs the result as a new RSS feed. Look at the picture to see how it’s done.

Notice the category.0 / category / category.1 part. Yahoo Pipes is a leaky abstraction. It pretends to protect you from the ugly details of XML, but when your blog posts have either one or two categories, like mine do, you still need to know that to an XML parser there’s a difference between a single node and a node list.

To most people that last sentence made no sense at all. XM..what?? Neither will most of the modules in the Yahoo Pipes toolbox, such as regex and loop. In other words, this is a service for people with technical instincts. It’s programming, just prettier.

But still: Really, really cool.