My OPML Wizard idea just expanded. Say you had a large OPML file like Tod Miffin's directory of podcasts. Then you make it collapsible and expandable like good old outliners using Ajaxian coding. Finally you throw in another web meme, the shopping cart, so people can select the items they like. When they view their "shopping cart" they have their own, personalized OPML. Using this concept as with a directory of podcasts, you then have your own OPML directory of podcasts that you could import into your favorite RSS/Podcast reader/aggregator.

If you are having trouble imagining this, think of Gmail interface where you manipulate a list of podcasts instead of email.

Obvious my project for building a XSLT wizard just got very ambitious. And if I could get it working, it would be useful for any site that hosts more than one RSS feed.