Video Not Available

video removed for copyright while similar videos were not?
"we are likely either not aware of them or do not have reason to believe they are infringing"

Well, right, but it is all still mysterious. After three weeks of seeing what items from my video blog become "unavailable", it seems like there must be some people who have the job of requesting take downs of videos...but many of these videos are up for months before they are taken down. Does that mean that the people making the take-down requests do not know how to search YouTube or that the search function is so over-loaded that they cannot find videos until they work their way up in the rankings or can it take months to get YouTube to remove a video?

I've also seen some videos where comments are not allowed (but not many). I might be wrong and not remembering exactly what happened, but I had been looking closely at the two Cat Stevens videos that were in my video log. I had noticed that one had comments blocked, then the next day I found that it was removed from YouTube. Why that one? It would sure be interesting to know what goes on "behind the scenes" of YouTube.