The EU recently passed a new copyright law that potentially creates massive problems for private individuals uploading content to the internet. Copyrighted music in the background of your video can create a copyright violation take down situation.
https://en.wikipedia.org/wiki/Copyright_law_of_the_European_Union
The EFF has a good article explaining some of the issues surrounding the new EU law.
The end result is, these days, you really need to be careful of what you put up, and if you make any money from your videos, you want to protect that work and know it will be safe.