The essential idea behind Web 2.0 is that it is user-based, user-generated, and interactive. Blogs are Web 2.0 because the platforms (like LiveJournal, Blogger, Movable Type, Wordpress) provide no content. They merely provide frameworks for content—users like you and me generate the content. Blogs are interactive—we can comment on blog posts, or on LiveJournal we can even have threaded discussions.
But these ideas aren't new to Web 2.0.
In the beginning of what we might call Web 1.0, the majority of web sites were user-generated. Some companies were quick to jump on the bandwagon, but when the web was new, most of the interesting web sites were .edu—not .com. The pages were created by students and faculty. The web was user-generated. One of the more common web-based applications (or CGIs, as they were often called then) was a guestbook, where visitors to a web site could leave comments for the creator—much like blog comments today. Threaded discussion boards appeared not long after, followed by real-time chats. Web 1.0 was interactive.
But in Web 1.0, you typically needed a shell account and some server space to post content. You needed to know HTML, and if you wanted a guestbook, you needed to install and configure a CGI.
Even before Web 1.0 we had user-generated, interactive online content. In 1992, I was a huge fan of the University of Minnesota's gopher site, particularly their lyrics search. The lyrics to popular and obscure songs alike were posted there and made searchable by a large number of users around the globe. And the contributors' e-mail addresses were often listed, so I was able to communicate with a fellow in Colorado who had typed up many lyrics of industrial songs of which I was a fan. Other technologies available at the time were IRC (real-time chat) and MUDs (Multi-User Dungeons, early real-time mutli-player games). All of these were frameworks in which the users interacted to create the experience.
But even though gopher was easy to use and simple to navigate, you had to know that it existed. You needed a computer, network access, and if you wanted to interact with anyone, you needed an e-mail address. These prerequisites seem pretty standard now, but in 1992 they were less common.
Even before Gopher we had user-generated online content and interactivity. In 1989, I started dialing in to a lot of BBSes (Bulletin Board Systems) in the Lansing area. These BBSes were hosted by individuals (SysOps - Systems Operators) from their homes, usually on a 2nd phone line, or sometimes even from their primary line (but only between certain hours of the day). Like Web 2.0, the BBS software provided a framework, but the users generated the content. Only one user could dial in to a given system at a time, so there were at most 2 concurrent users (a dial-in user and the SysOp). You could chat in real-time with the SysOp, or you could participate in discussion boards, send private messages to other users, play multi-player (but asynchronous) games, and even illegally share copyrighted files. Sure, the experience was not graphically-rich—it was text-based, and typically monochrome—but the essential elements of Web 2.0 were there.
But the prerequisites to participating in a BBS, much less hosting one, were even more rare in 1989. I didn't even know that BBSes existed, or what they were, until a school classmate told me about it and gave me a couple BBS phone numbers.
The pieces of the user-generated, interactive chimera were all there in 1989, and probably years before. (I recently read that Nintendo created a network for the Japanese version of the NES, the Famicom, that in 1988 that offered online stock trading, shopping, and e-mail).
There is no Web 2.0 technology. But there has been a shift—the technology has become more and more accessible. Blogs, networking sites, bookmarking sites, photo-sharing sites, all allow people to create content without any special technical knowledge. And although there are still prerequisites to access the web, the prerequisites are now common. Web 2.0 is just a democratized version of Web 1.0 and its predecessors.
I've changed my mind: Web 2.0 is not a chimera. Web 2.0 is Snuffleupagus—he was always there, but now everyone can see him.