RSS is a technology and with the launch of Windows Vista it will be in the mainstream in the most obtrusive way, but is this just the beginning? RSS is getting old, it's about the same age as the Google, for example.
My take is the that the technology is not going to be the star, but the implementation in the form of a service will be. Google is just a front end for a crawling strategy and an algorithm, Page Rank, that weights the resulting hits for relevance and popularity--it's a pretty blunt instrument, but it is brilliantly packaged so it swept the world. RSS has been skinned by various aggregators and, now, Vista, but it hasn't and probably won't be referred to as the transformative event in recent years, despite its incredible significance.
We're not HTML users, as a member of the audience here points out. We use the Web, which was productized as the browser, which operates on the foundation of HTML. Aggregators are the zenith of RSS? I don't think so. But how early are we?