Reminds me of TinEye's multicolr demo [0] that searches through CC-licensed images on Flickr. Their multiple color feature was really nice (however they don't have shuttershock's keyword filtering.)
I wonder if anyone ever bought TinEye's color-search-engine-as-a-service [1]. The as-a-service model seems really awkward for something that requires so much integration, and this new shuttershock feature (developed from the ground up) seems to confirm this.