I think the opportunity to reign in public perception about photography copyrights is all but over. In a sad way, it's a moot point now.
The best you can do is create so much incentive for people to participate in the legitimate economy, that the efforts to pirate become less interesting and less profitable, yielding a progressively smaller proportion of that industry’s total economy.
Seems Yahoo / Flickr / Tumblr had made a recent change towards sharing with atribution. They have dropped Wordpress / Blogger / Live Journal sharing support ( though sharing with HTML code is still possible ). It seems this includes sharing with Facebook and Pinterest also carries attribution.
FYI, I found that since I turned sharing *on* in Flickr, enabling sharing to Tumblr especially, the number of improperly-posted photos of mine on Tumblr has plummeted. Everything I find there now is properly sourced and linked from Flickr.
I have heard of Reddit but know nothing about it.