I had a good experience with delicious and i started my own account. It is http://delicious.com/elainemarie27. I could see using this as a tool It is a nice way to bookmark your sites so you can use them anywhere. Next, Technorati I found to have some nice instructional videos. The one thing I found with this site is that there are a lot of results almost too many for my liking. I could see spending a great deal of time just trying to find something you are looking for.
YouTube, I am not sure of. I have seen some things on there that others have showed me but never used it before today. The video I chose was a volleyball video on serving and receiving the ball. I believe it shows some good technigues and different drills that I could use as I have been a volleyball coach in the past, and will in the future again. I could see this being used in a class to a point but a good chunk of them I have seen I feel are out there for entertainment purposes and not very educational.