As I shared in a post earlier this month, downloading videos from YouTube via a third party tool is a violation of YouTube's terms of service (TOS). Despite that fact there are many teachers who do attempt to use third party tools to download YouTube videos. One of the most popular of those tools, KeepVid recently changed its tune. KeepVid no longer supports downloading videos from YouTube, Vimeo or other video sharing sites where the terms of service don't allow it. A visit to KeepVid today will just give you a bunch of information about why you shouldn't download videos illegally.
The new information on the KeepVid homepage strikes me as being hastily thrown together to comply with a legal request. But that's purely my speculation based on many years of filing DMCA take-down notices and dealing with the legalese of an online business.
If you'd like to learn more about copyright issues as they relate to classrooms, watch this free webinar that Beth Holland and I hosted late last year.
H/T to Make Use Of for the update on KeepVid.