Earlier this month, Bing announced a new feature within image search to do visual searches based on selecting portions of an image that comes up in your image search results. So if you see a table and on the table is a pitcher you like, you can zoom into the pitcher on that image of a table and get image search results just for the pitcher.
I tested it myself and it seemed to work okay. I searched for [kitchen table] and up came results, I selected one image:
Then I selected the "search within this image" button and Bing gave me a cropper tool to adjust what part of the image I wanted to search on. I selected that yellow pitcher:
Bing responded with similar related images and then search phrases including pitcher, tea, teapot, food, flower, and mug. Not bad at all.
A WebmasterWorld thread has a mix of feedback, one user said "it is not bad at all" while another said "it doesn't work very well." I guess it depends on the query and the images you select?
Forum discussion at WebmasterWorld.