I remember seeing a lot of stories 6-12 months ago that talked about the 1% rule for user-contributions to participatory web sites. 1% create content, 10% interact with it, and 89% pass it by.
But according to this fairly recent article from Reuters http://www.reuters.com/article/internetNews/idUSN17436388200..., the percentage of people that actually generate content is even lower. For example, only 0.16% of visitors to YouTube upload videos. And 0.2% of visits to Flickr are to upload new photos. Wikipedia fares better with 4.6% of visits used to make edits. But it's all a far cry from 20% of users generating content.
But according to this fairly recent article from Reuters http://www.reuters.com/article/internetNews/idUSN17436388200..., the percentage of people that actually generate content is even lower. For example, only 0.16% of visitors to YouTube upload videos. And 0.2% of visits to Flickr are to upload new photos. Wikipedia fares better with 4.6% of visits used to make edits. But it's all a far cry from 20% of users generating content.