A Web 2.0 “Sociological” point of view is probably the most interesting analysis, mainly because it can be really considered as the very network revolution. Web 1.0 could rely only on a kind of link: the one obtained from <a …> tags; its purpose was (and still it is) to allow the connection between two different documents according to their content or other criteria (they’re often marketing-oriented). Thus the resultant network was made up of several (pseudo-)static or slowly changing nodes which connectivity was always bound by lots of limitations (first of all a spare knowledge about similar resources). The pure hypertextual technology was certainly great, but its weaker point was that of hiding the human beings, with their mutable nature, who were always behind the origin and development of each document (or web page).
Web 1.0 was just like a geographical network (like a city map, for example) where human action is seldom considered as a predominant factor and often not regarded at all. The main difference between Web 1.0 and Web 2.0 is, therefore, a radical change of view: every sub-network is now constituted by entities which can behave in a way that is isomorphic to their generators, and so, even if we cannot think of a global techno-human network yet, nowadays we may be present to the very genesis of many “social-made” networks.
Actually, this transition began in a period when the word “Web 2.0″ was completely unknown and a lot of new peculiar technologies didn’t yet exist: several communities introduced a kind of “built-in” network which participants should model according to their needs. Each member shared a common space where any node was created, modified or deleted without a strong central control; of course all the connections were established in a dynamic way, just like the very attitude of people in a small town, and their “meaning” could change reflecting the type of relation existing between two or more members.
It was probably thanks to those communities that the web “version-transition” could start, each small innovative idea was a percentage point towards a new “release”, until the attainment of a breaking point, a moment when it’s unavoidable to notice a clear difference. We are living in such a moment and can expect a new extraordinary revolution in the next few years.