From the article:
The report shows that In the US, the number of users of user-generated content will hit 101 million by 2011, up from the 2006 estimate of 69 million, while the "generators" lag at 91 million.
This is not so surprising. Not everyone is willing to put their homemade video on the Internet. It is the same as in many activities, you have a core of people who do and a lot of people who look and lurk to see what is going on.
What about you? Do you post USG on YouTube? Do you use a webcam when you participate in social networks? Why or why not? Tell me.