Why is RSS important? Because it says "here's what's changed on the Web." When I started building Web sites in 1993, it was very clear then that people visit sites that get updated frequently. That's still true. Now, however, we have a new tool, RSS, that tells us what's changed. I no longer have to limit my reading to sites I know get updated frequently. Instead, I get pinged whenever sites I'm interested in change. That's a fundamental shift in what the Web is. In fact, its something brand new. Doc Searls' son Allen Searls calls it the World Live Web. I like that.