In recent weeks, social sharing site Pinterest has come under a large amount of fire for the ease with which images can be transmitted without any acknowledgement of their original source, and a flagrant disregard for copyright. Pinterest runs by allowing users to "pin" content they find on any website onto their own board, and share it with their friends — however the snippit of code that pulls the image and content onto Pinterest made it easy to do so without proper attribution.
Recently Pinterest made moves to rectify this by releasing a small piece of code that websites could embed to block being able to "pin" images, which, according to VentureBeat, Flickr has now adopted. Now, all non-public and non-safe pages, and all images where the member has disabled sharing, will block Pinterist. Anyone who's used Flickr substantially has probably hit those blocked images before, which handily protect against people just downloading them with a click or two.
As always, there are ways around these blocks — either by diving into the source code, and pulling out the image URL, or just by a screencap. However, the barrier is probably enough to stop many people from going into the extra work required, and will hopefully do something to stop the rampant abuses you see on Pinterest. Now, if only someone would do something about Tumblr and non-attribution.