I wonder if Google's will work the same, or if it will be possible to find other images that are similar, but not based on the same image? That's what I really want.
As a rough analogy, consider a textual example: Find a sentence similar to "It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife." Now, if you enter this sentence in Google, it retrieves documents that contain it, in TinyEye fashion. What other similarity is desired? Should it retrieve essays on Austen, on marriage, 17th century English literature...?
If you are interested in image similarity search, check out the Pascal challenge (http://pascallin.ecs.soton.ac.uk/challenges/VOC/voc2011/inde...). The advances in the last 5-6 years on object detection and visual feature extraction (which image similarity relies on) is amazing.