There is an interesting discussion going on about the similarities of rss feeds and the concept of subscription.This guy
says that if you can read a particular web site, then you are, in a sense, subscribed to it. He has this point of view, apparently, because he mainly uses a feed aggregator. I think that is a very forward looking point of view, however maybe it has some holes.
His point of view seems to be that browsers will become feed aggregators. I'm not so sure of this idea. I don't know how an aggregator would handle static documents, such as a reference for a programming API.
In my opinion, there is a fundamental difference between the "live web" (things such a weblogs) and the traditional "static web." The difference is fairly subtle, and I don't know how to categorize it well... something to think about.