I love my.discoveryeducation.com and use it frequently to embed videos into my power points for IPC. They have great short video segments that work well with what I am teaching. I have had a couple of problems with the sound but I usually can work it out. I looked at teachertube.com and had a little trouble with it but I will have to investigate that more.
Buoyancy video http://player.discoveryeducation.com/index.cfm?guidAssetId=D6766517-253E-4232-AE60-859A915C5F37
Mixtures and solutions http://player.discoveryeducation.com/index.cfm?guidAssetId=EAB00DCD-E1CF-469C-99E7-A0AC8699954A
Copyright and fair use. It looks like if you use things for school and classroom that we are good to go. Nothing should be use out in the public unless you have the copyright permission. I already knew some of the info for videos and we used to be able to get good science videos from discovery channel but that has gone away but we now have my.discoveryeducation.com so that works great.
Dropbox is another way to share files. We use the MHS science share file already in IPC. I could see that this might be good if you are afraid of losing things on the server.