We just had something happen that plays into this issue.

Someone had posted one of our clips on a tube site illegally. A commerical website then embedded the clip into their site and was publicly displaying it and profiting from the traffic. (we think it was actually the secondary website owner that had posted the clip to the the tube site to get free bandwidth, but we couldn't prove it.)

We went after both the tube site and the secondary website that was displaying the clip. Both of them ended up having to pay thousands of dollars for just one clip.

Lesson: Be careful what you post on your site! Free isn't always free! Even if you are not the original source of the clip, if you are publicly displaying it and profiting from it, you become liable as well.