It looks like today I'm going to post another definition of a term that is being thrown around as a poorly understood buzzword.
What is Web 2.0?
Generally speaking, Web 2.0 is the use of the web as a platform. Websites don't work one way anymore - they're interactive networks. Websites serve as a platform for users to talk and share various types of information.
Wikipedia cites Flickr as an excellent example of Web 2.0. Flickr encompasses Web 2.0 characteristics because it's interactive - users share photos. Everyone has access to these photos when they're uploaded. Different users can tag photos so that the tags become increasingly refined. People can comment on the photos. And though Wikipedia didn't mention this: Flickr constantly updates and refines its own software based on user feedback as much as every half hour!
Naturally, Web 2.0 websites work better the larger the number of people who use them. Web 2.0 is about information and connectivity, and so the more information is uploaded, the better your results. Does anyone here remember using search engines ten years ago? Wasn't so great, was it? Now search Wikipedia for something. With it's radical trust model of thousands of users uploading all sorts of "trivial" (niche) data, you can find anything. (Hint: Use Google to search Wikipedia, though; Wikipedia's own search function isn't so hot.)
The best explanation I've found of Web 2.0, however, is not on Wikipedia. It's an article from Tim O'Reilly titled, appropriately enough, What is Web 2.0. Specifically, I really like his use of the term "collective intelligence," because it's hugely significant. According to O'Reilly, in a Web 2.0 world, you must treat your users as "co-developers." The interactivity of today's web means you don't get a monopoly on information. Everyone gets a voice, and the voice of everyone is what acts as your leverage.
Think of the biggest sites on the internet. They're not one guy publishing a zillion times a day. The sites are just platforms for everyone to participate. Take Google - their model literally works off the participation of every single person on the internet.
Where We're Headed
I have no idea. Don't ask me what Web 3.0 is, because I don't know, and neither does anyone else, no matter what they tell you.
I do believe that, in the future, every piece of software will be available online. Instead of installing Microsoft Word on your computer, you'll just have an account on Google Docs. Instead of installing an operating system, you'll just log on to a website which is basically a customized collection of your bookmarks. However, bookmarks will be what we know as programs.
We won't use things like USB keys or DVDs to hold data. It'll all be online and in secure data centres around the world. Why? Well it opens things up. Think of the Macbook Air. No CD or DVD drive means it can be smaller. And why go through the trouble to create a new mini CD or mini USB or something for an iPhone when you can just get everything you need off your "home" or "desktop" website account? As connectivity speeds increase there's no reason not to go this route.