The happy birthday song has always been a bit of a mystery to me since I was young. I was always curious why each restaurant had its own version of the song and they weren't able to sing the song that we always heard at birthday parties and at school. I later found out it was under copyright protection, as is explained in the linked article, and needed to be licenced to be used in anything. The song and it's owner, Warner, has since come under some lawsuits regarding the song belonging to the public domain. The licensing fees that Warner has collected are huge and it looks like the licensing fees they have collected can be taken back if this is found to be the case. From what I have read it looks like that could have the case since the song is the same as an old song, good morning to you, that was written over a century ago. This would be significant because the company has profited off the public domain work for a long time and could face massive payouts. This is interesting to me because it has always perplexed me that the song had to be paid for every time that it was used in a public place or movie, but it is such a common song that it didn't seem possible for someone to own the copyright for it since it has been around for so long.