does any body know

Hey everyone, does anybody know if its illegal to give away free mash ups. I have made a few and been giving them away but some one told me I could get done for it. Is this true?

Don't I have to be selling them or claiming that the originals are mine to make this illegal?

thanks

Officially it is illegal, because it contains copyrighted material.
Giving away a bootleg/remix of a tune is also illegal, as it contains copyrighted material.

That doesn't mean that usually nobody cares if you do.