Google Social Search launched over a year ago. It really hasn't caused much of a stir over the year. But now there are signs that Google Social Search is being expanded to Google Image Search.
A Google Blogoscoped Forums thread has Websonic.nl saying he sees it in his Image Search screen. He shared a few screen shots, but here is one:
As you can see in the left bar, he can limit the search results to specific friends of his in his social circle.
I believe this is new for image search.
Forum discussion at Google Blogoscoped Forums.
