(found this via the Frameworks listserv. In other words, through Dark Social.)
Here's a pocket history of the web, according to many people. In the early days, the web was just pages of information linked to each other. Then along came web crawlers that helped you find what you wanted among all that information. Some time around 2003 or maybe 2004, the social web really kicked into gear, and thereafter the web's users began to connect with each other more and more often. Hence Web 2.0, Wikipedia, MySpace, Facebook, Twitter, etc. I'm not strawmanning here. This is the dominant history of the web as seen, for example, in this Wikipedia entry on the 'Social Web.'