Yup, I have. And saying "fair use" makes about as much sense as saying "abracadabra" -- it's an incredibly narrow set of criteria that you can use if you're actually in court, not a magic word you can utter to make things work to your advantage.

Meanwhile, the assumed default status of anything created in a Berne Convention country in the past 90 years or so is still "all rights reserved".

So you're saying Pinterest only copy US created content to their servers?