The United States Copyright Office will do a study of possible abuses of the takedown procedures associated with the Digital Millennium Copyright Act Safe Harbor process, and is seeking public comments. Electronic Frontier Foundation has posted the document called a “Section 512 Study Notice of Inquiry”.
Many of the most abusive takedowns seem to be instigated by large public companies that believe they have a fiduciary duty to protect intellectual property from posts, especially on YouTube, that in a “real world” could not possibly lead to piracy or have a material effect on their ability to make money from their content. These include many parodies and mashups.
I still, when picking videos to embed, try to stick to items that appear to be posted by the original content owner (like a media company, book author, or motion picture distributor) whenever possible.