Everything You Need to Know About Web 2.0

TechSoup - "Web 2.0 is a category of new Internet tools and technologies that focuses on the idea that the people who consume media, access the Internet, and use the Web shouldn't passively absorb what's available -- rather, they should be active contributors, helping customize media and technology for their own purposes, as well as those of their communities."

TechSoup article can be found here.