If you want to create an educational video sharing site, screencasts are an essential component. Since video has become so much more popular and affordable, many content creators are turning from the traditional text tutorial with screenshots to the more information rich screencasting format. If your educational content revolves around a computer, then you really need to be making screencasts to obtain the maximum levels of engagement and sharing.
Put simply, a screencast is a video recording of all or some part of your screen along with audio narration, screen captions, and sometimes a music soundtrack. In the old days, it was a pain to make a high-quality screencast, but both software and hardware has improved to the point where it’s fairly straightforward with the right tools. Read more
Video sharing sites pose a particular set of problems for search engine optimization. Google’s crawlers can’t interpret video content and so rely on the textual content and markup that surrounds the videos to get an idea of the terms for which videos should be ranked. It’s likely that Google is going to get better at interpreting video content in the future — they’re certainly working on 
