I had the same thought.i think they are going to use this to flag similar icons(and to show recommended images).so, most likely it'll be reviewed by a human.

Edit:

From the last paragraph. > we will be using the algorithm in the future on Iconfinder to warn us if a submitted icon already exists in our collection but it can also have other practical uses. For example, because images with similar features have the hamming distance of their hashes close, it can also be used as a basic recommendation system where the recommended images are within a certain hashing distance of the current image.