Jonathan Coulton strikes back by re-releasing his own song
I think it's important to realize exactly what Fox is (regularly) doing here.Fox/Glee finds a popular song.  Fox/Glee wants to do a cover.  Fox/Glee searches the internet to find a popular cover of the song.  Fox/Glee does their cover in the same style, by having musicians play/record a note-for-note re-creation of that popular cover.  Fox/Glee pays mechanical royalties to the original songwriter/publishing-company, pays absolutely nothing to the arranger that came up with the stylized cover version, and refuses to acknowledge them.This is 100% legal, no matter how creative the arranger was in coming up with their cover.  If the cover artist was granted a mechanical license, the only copyright protection they were granted was to their sound recording.This is also not the first time it has happened.  In episode 1, Glee's cover of Don't Stop Believing was practically identical to a famous a cappella arrangement (from a college a cappella group that released a cd and won some awards from it).  There was another "regionals" number that was largely identical to another similarly famous a cappella arrangement.It's lousy behavior and I think they deserve every bit of blowback for being poor citizens, but it is technically legal.(Big asterisk: There is reason to believe that Fox actually took Coulston's karaoke version of BGB and recorded vocals over it.  This, in contrast, would be a copyright infringement.)