Not only that mate, I use keepvid to download videos I like to keep as I know they will not be up on the youtube for forever.
But now I am being forced to download videos I want to just watch and downloading them will use the full force of my 120mb line such as earlier I was downloading a 500mb 1080p commentary and it was downloading at over 10mb/s whilst I was stuck on buffering on 30 seconds.
I have 3 different browsers which provide the same results and its only been the past 1-2 weeks this has been happening. First it was not being able to change video quality I just get endless spinning from the cogwheel and then I am waiting for about the length of the video just to see 1 minute of it.