It’s not perfect, but I’m consistently impressed by Tumblr’s automatic source-linking function. Sure, there are the jagoffs that will manually strip an image of watermark. But Tumblr made it so that it’s harder to not credit sources, and they did it in an unobtrusive way that anyone who cares about attribution would find helpful.
Stolen content still happens all the time on Tumblr. But now it’s generally the product of malicious intent rather than just laziness, an affliction that besets a much broader swathe of users.
We’ve had it for almost two years now, but I don’t think it ever got the recognition it deserves. What an accomplishment.