I am an attorney (and as far as I can tell, the author is not one, so take his "analysis" with a pillar of salt). This is not legal advice though.
With respect to the following paragraph:
"So, if you snap an awesome photograph, upload it to your blog, and someone pins it, that person is either (1) claiming exclusive ownership of it; or (2) giving Pinterest your consent to reproduce it (and you just thought you were being flattered)."
Actually, no. You can't transfer a right you don't have. All rights to a work are vested in the author of a protected work; only the author can consent to any of the activities protected by copyright.
It's just like selling a house you don't own. First, you're committing fraud if you falsely represent that you have the right to sell it; and second, the actual owner isn't bound by anything you have done (the deed doesn't go to the putative buyer).
And there in lies the problem with TOS (or is the problem with the law?) if one needs to be an attorney to understand them, what hope is there for the ordinary folk - just saying. No wonder people just click through.
This is my issue with the article. If your rights as content creator are violated by Pinterest, then that's between you and Pinterest. If Pinterest were to say "but user 4023 said it was ours to use!" my reaction would be "so what?"
With respect to the following paragraph:
"So, if you snap an awesome photograph, upload it to your blog, and someone pins it, that person is either (1) claiming exclusive ownership of it; or (2) giving Pinterest your consent to reproduce it (and you just thought you were being flattered)."
Actually, no. You can't transfer a right you don't have. All rights to a work are vested in the author of a protected work; only the author can consent to any of the activities protected by copyright.
It's just like selling a house you don't own. First, you're committing fraud if you falsely represent that you have the right to sell it; and second, the actual owner isn't bound by anything you have done (the deed doesn't go to the putative buyer).