Here's a great slide from Mary Meeker's Web 2.0 Summit presentation (download at Morgan Stanley) showing the dominance of social networking sites. If you haven't been able to get management to buy off on your social media plans, circulate this slide.

These are the top 10 domains now compared to two years ago as measured by Alexa. The red sites on the left have dropped out of the top 10 giving way to the green sites. Web 2.0-oriented sites can now claim six of the top-10 slots, including four social networks: Facebook, Orkut (Google), Myspace and Hi5, and two user-generated sites:  YouTube and Wikipedia.    

Also according to Morgan Stanley, worldwide Internet use passed the 1 billion mark early last year, and is estimated to hit 1.3 billion this year. The chart also shows the distribution of Internet users by region. Note the dominance of the red part of the bar, and, no, that's not Republicans, it's Asia/Pacific.