[Acenoid]

Correct! Of course you need to have a grip on the copyrighted stuff. Especially in your own store.

And FB & YT are huge sites, generating so much revenue, that it might also be not cost effective for the copyright owners to go forward against such copyright infrigements. I think for music there are deals that YT pays for certain videos money to cover for the music. Other times the sound just get muted, just because in the background an "unauthorized" version of some song is played...

Anyways I think copyright is a sinkhole, which can cause a lot of trouble for your company.

It's completely okay if the software offers import / export functionality for private / fair use reasons, but public selling / posting of such content is not allowed and could also be followed up with c&d orders or worse...