The takedown process is partially mechanical but as the years go by, there are purges which are probably done by interns who just blanket out huge swatches. You can counter the takedown. This is important especially if the video have a variety of comments which demonstrate public reaction and thus could be historically significant, even if it's a minor thing.
There's a thread for posting about full versions of the SW movies found on video hosting sites, and a few fan edits are in that list. Please add the Revisited ones if you can.
http://originaltrilogy.com/forum/topic.cfm/Movie-Full-Active/post/469897/#TopicPost469897