I'm surprised that no one else has been commenting about the disappearance of so many watermarked images from Google's image SERPs. By my reckoning, in my niche, they have cleared-out some 90% of them with many good images being replaced by inferior and in several instances, totally incorrect ones.
I'm guessing that Google hasn't liked all the watermarked images appearing in its SERPs
Since I've had so many images stolen over the past 14-15 years today I've decided to let those specific images be indexed without watermarks to see what, if any, difference it makes to traffic. I'm doubting very little since myself, and many other image creators, saw such a dramatic fall in traffic after 28th January 2013, however one never knows without experimenting.
All new images created in the past 2-3 years will not be uploaded without watermarks plus I certainly will not be relaxing my hotlinking defence.
[edited by: goodroi at 3:38 pm (utc) on Apr 14, 2014]
[edit reason] Looking forward to a productive experiment without editorializing [/edit]