There are as many definitions for Web 2.0 as there are people trying to define it. Some call it “when the back button doesn't work,” or all things Ajax, or the age of Really Simple Syndication (RSS). The one thing that is certain is that the way Web activity is measured has to adapt. Organizations still need to make decisions based on Return on Investment (ROI) or Total Cost of Ownership (TCO) analysis and need ways of evaluating investments in new projects.
Some of the potential benefits of Web 2.0 tools, like improvements in productivity, communication, or efficiency, are inherently difficult to measure. On the other hand, the enormous amount of User-Generated Content (UGC) or Consumer-Generated Media (CGM) creates opportunities to garner a deeper understanding of target audiences and is measurable.