It's hard to write a story or post about Pinterest and copyright law without at least one reader leaving a comment along the lines of "What about Tumblr?" Indeed, comparisons between the two sites are fairly obvious: while Tumblr is more of a blog platform and Pinterest is more of a link-sharing site, both are set up to allow users to easily share content they find on the Internet, and both do a great job of displaying visual content -- whether or not the person sharing that content has rights to share that work.

Why we should read TOS when we sign up...

And here's the kicker: The user agreement of both sites has language requiring users indemnify them against any copyright claims, Bradley said. They can do this by claiming proietections for service providers included in the Digital Millenium Copyright Act.