incrediBILL - 6:46 am on Feb 29, 2012 (gmt 0)
More importantly, copyright isn't optional, which I've been complaining about since the first cache page was displayed in a SE. Pinterest and all the others should assume by the letter of the law that they DO NOT have permission to copy and display anything unless they are expressly ALLOWED.
Copyright has never been OPT-IN, it has always been OPT-OUT if you wanted to release to the PD, until scrapers on the internet somehow decided if you publicly published something it was already public domain.
Why this has never been taken to court and reversed I'll never know but my theory is nobody with deep enough pockets has decided to fight the fight and assume by now it's too late to reverse the trend.