I am constantly reading comments from people who think that Web 2.0 is about Ajax. If that were the case we would have witnessed Web 2.0 a long time ago, it's nothing new, but gained popularity once it was coined as “Ajax” by Jesse James Garrett and Google launched its map service.
In reality, Web 2.0 is really about sharing and communication. Sharing involves the exchange of data or the exchange of ideas. The next generation of web applications is about bringing social tools to the web that allow people to make better decisions and manipulate data for specific informational purposes. It’s a decentralized approach that allows rapid exchange of ideas and development of applications.
There are many examples in my view, but here is a short list:
One central resource for all of your IM’ing tools.
Excellent photo sharing service with an easy API to integrate photos into other applications.
Del.icio.us and Digg
Social Bookmarking services to share, organize, and rank URLs on the web.
Although it’s not entirely grouped with Web 2.0, I feel the incredibly fast-paced development of new VoIP communication tools will play a big role in the future of social applications.