From http://ets.tlt.psu.edu/white-papers/hot-team-grassroots-video/:
Most of the content in YouTube is grassroots video: short videos posted by ordinary people who are recording what is going on around them. Most of these videos don’t have special lighting, sound, scripts, costumes, or props. In a 2008 survey of Penn State students, we found that 85 percent of them were watching videos on YouTube or a similar service and 17 percent were uploading videos of their own. That means that 14,000 students at the university are creating and uploading video. These videos are easy to search, rate, share, comment upon, and embed in other locations, such as blog posts.
How does grassroots video work and what are the implications for teaching and learning? To answer these types of questions, we formed a Hot Team, which wrote a Grassroots Video White Paper. We are also working on a grassroots video about grassroots video. It will be added to this post when it is ready.