I generally haven't been inclined to block YouTube in schools. Despite the countless videos of kids skateboarding, extraordinary amounts of educational content are there for the taking. Here, for example, is everything you ever wanted to know about distillation:
Unfortunately, it looks as though the junk is quickly on its way to overwhelming the good. Ars Technica is reporting on the so-called carpet-bombing effort to fill YouTube with pornography:
Today, May 20, has been deemed "Porn Day" by denizens of 4chan and eBaum's World, with an organized group of users from the sites uploading video clips of explicit, adult content en masse in an attempt to overwhelm the search results. In actuality, it appears that content was prematurely uploaded on the afternoon of the 19th. YouTube has already taken some steps to fight back, but it's disturbingly easy to find stuff you really don't want to see, and the uploaders are changing tactics.
What this means is that we need to train our teachers and provide them with easy tools to deliver appropriate content to their students. No more, "Hey kids, put together a PowerPoint presentation and feel free to search for some resources on YouTube." YouTube does make it incredibly easy to embed video on the web and now has tools for excluding those "related videos," which are all too often a source of said junk.
Therefore, we need to train our teachers to place videos on their own websites or blogs or, better yet, use a site like Fliggo to really isolate useful video content from the rest of YouTube. How many of your teachers know how to embed a YouTube video in a blog? There's no need to throw out the baby with the bath water in terms of online video, but there is a real need for increased vigilance and helping teachers find new ways to clearly direct instruction around useful video.