Finally, Salim is blogging. Welcome! What took you so long. More please! Disclosure blah blah blah!
From Evolution of the Internet.:
After the rollout of messaging and request/response, we are now entering the third wave of the internet, the publish/subscribe decade. The web has been phenomonally successful and the amount of information available on it is overwhelming. However, (as Bill rightly points out), that information is largely passive - you must look it up with a browser. Clearly the next step in that evolution is for the information to become active and tell you when something happens.
Blogs and RSS are the first general manifestation of publish/subscribe. The real reason for the explosion of RSS/blogging is the ability to "subscribe" to a blog or feed and be told "whenever". We can expect this theme to dominate the next several years of the internet.
What Bill refers to as the "active web", or Doc as the "live" web, we refer to as the pubsub web (ok, so we"re not the greatest marketers). Our whinge would be that it"s the implementation of publish/subscribe on the internet that will make the web active. People often talk about PointCast as the first major effort to "live" up the web. It was an effort, but not very well implemented.