There are more interpretations of Web 2.0 that there are of Shakespeare’s Sonnets. It is certainly not a “thing” but more of a culture change. It is not one set of technologies; it is partly a change in the way technical development is approached.
If one is looking for a nutshell in which to find the answer, the simplest place to start is what it used to be like way back when. Say four years ago. In those heady days, brands would create a website, we shall call it www.product.com. Using various straight line methods (advertising, emails etc) we were implored to go and visit and indulge in the carefully prepared corporate messages.
Nowadays, we create and control the conversation and opinion. And that’s called User Generated Content (UGC). Through blogs and forums and dedicated websites Tom, Dick and Harriet are holding forth on what they think of product.com, which is not necessarily what product.com wants them to think.
This phenomena of sharing and collaborating is what the Internet was about at its very creation. It just had to go through a few years of corporate hijacking to get back to what it was always supposed to be.
Brands are rapidly having to change their outlook as they ask themselves how to deal with Web 2.0. In a nutshell? Understand what Web 0.0 was all about and you’ll be half way there.