Now, of course, "dynamic websites" (i.e., database-backed sites with dynamically generated content) replaced static web pages well over ten years ago. What's dynamic about the live web are not just the pages, but the links. A link to a weblog is expected to point to a perennially changing page, with "permalinks" for any individual entry, and notification for each change. An RSS feed is thus a much stronger link than, say a bookmark or a link to a single page.
RSS also means that the web browser is not the only means of viewing a web page. While some RSS aggregators, such as Bloglines, are web-based, others are desktop clients, and still others allow users of portable devices to subscribe to constantly updated content.
RSS is now being used to push not just notices of new blog entries, but also all kinds of data updates, including stock quotes, weather data, and photo availability. This use is actually a return to one of its roots: RSS was born in 1997 out of the confluence of Dave Winer's "Really Simple Syndication" technology, used to push out blog updates, and Netscape's "Rich Site Summary", which allowed users to create custom Netscape home pages with regularly updated data flows. Netscape lost interest, and the technology was carried forward by blogging pioneer Userland, Winer's company. In the current crop of applications, we see, though, the heritage of both parents.
But RSS is only part of what makes a weblog different from an ordinary web page. Tom Coates remarks on the significance of the permalink:
It may seem like a trivial piece of functionality now, but it was effectively the device that turned weblogs from an ease-of-publishing phenomenon into a conversational mess of overlapping communities. For the first time it became relatively easy to gesture directly at a highly specific post on someone else's site and talk about it. Discussion emerged. Chat emerged. And - as a result - friendships emerged or became more entrenched. The permalink was the first - and most successful - attempt to build bridges between weblogs.
In many ways, the combination of RSS and permalinks adds many of the features of NNTP, the Network News Protocol of the Usenet, onto HTTP, the web protocol. The "blogosphere" can be thought of as a new, peer-to-peer equivalent to Usenet and bulletin-boards, the conversational watering holes of the early internet. Not only can people subscribe to each others' sites, and easily link to individual comments on a page, but also, via a mechanism known as trackbacks, they can see when anyone else links to their pages, and can respond, either with reciprocal links, or by adding comments.
Interestingly, two-way links were the goal of early hypertext systems like Xanadu. Hypertext purists have celebrated trackbacks as a step towards two way links. But note that trackbacks are not properly two-way--rather, they are really (potentially) symmetrical one-way links that create the effect of two way links. The difference may seem subtle, but in practice it is enormous. Social networking systems like Friendster, Orkut, and LinkedIn, which require acknowledgment by the recipient in order to establish a connection, lack the same scalability as the web. As noted by Caterina Fake, co-founder of the Flickr photo sharing service, attention is only coincidentally reciprocal. (Flickr thus allows users to set watch lists--any user can subscribe to any other user's photostream via RSS. The object of attention is notified, but does not have to approve the connection.)
If an essential part of Web 2.0 is harnessing collective intelligence, turning the web into a kind of global brain, the blogosphere is the equivalent of constant mental chatter in the forebrain, the voice we hear in all of our heads. It may not reflect the deep structure of the brain, which is often unconscious, but is instead the equivalent of conscious thought. And as a reflection of conscious thought and attention, the blogosphere has begun to have a powerful effect.
