I find that many themes are created by companies...are these themes still open source and could the credits and links to those companies be removed without any legal problems
I find that many themes are created by companies...are these themes still open source and could the credits and links to those companies be removed without any legal problems
There's really no answer to this. The wordpress folks will tell you one legal opinion, the EFF will tell you another and the creators of those themes will tell you a third opinion.
Honest answer though: If you're going to have any legal concerns concerning usage, they're going to come from the theme creator. I would follow their rules. If you don;t follow their rules, they're the ones going to cause you problems.
If you're purchasing theme from the big name theme shops, most of them will let you do that.
But really, it can be specific to each place, so check with the theme company first.