[a-dub]

using fancy neural nets for learning hash functions from data is indeed pretty cool, but hash functions fit to data isn't new. see "perfect hash functions."

lsh is most famously used for approximating jaccard distances, which even if you're not doing stuff like looking at lengths or distances in l1 or l2, is still a vector operation.

lsh is best described in jeff ullman's mining massive datasets textbook (available free online), which describes how it was used for webpage deduplication in the early days at google.