I have used YouTube quite a bit for tutorial videos on various Algebra and Geometry topics. I had never visited the SchoolTube site before today, but found it a little less efficient than just using YouTube. I usually use Khan Academy and other math sites that I trust for instructional videos.
Here is a video that my Geometry students created for the semester review:
Here is a video from Khan Academy that would be useful for my classroom:
Dropbox is a great tool for the classroom. Prior to the break, the Geometry class created tutorial videos for each other. Dropbox would be a great place for them to put the videos so they could access them from anywhere.