Duncan Rawlinson has done something really nifty using RSS and OPML with the Grazr plug-in tool that I've used on this blog.
In constructing the plug-in, he chose RSS feeds that all had "meta-juice" on them, so to speak, where each represented an outside filter that selected for the most popular, forwarded, bookmarked or otherwise selected-for stories at the top of the pile of electonic chaff. Like I said, really nifty and terrific for discovery new ideas, stories and voices with very little effort. In a world suffering from extreme information overload, tapping into the power of metafilters is one of the few effective strategies I've found for staying aware, informed and entertained.
Hat tip for the link and discovery to Micropersuasion.