The domain of knowledge you're interested in is "information retrieval" (IR). Here's a textbook on the subject from some of the top minds in the field: http://

The domain of knowledge you're interested in is "information retrieval" (IR). Here's a textbook on the subject from some of the top minds in the field: http://www-csli.stanford.edu/~hinrich/information-retrieval-book.html http://www-csli.stanford.edu/~hinrich/information-retrieval-... I am not an IR expert, but one particular algorithm that you might find useful is latent semantic analysis, a.k.a. latent semantic indexing: http://en.wikipedia.org/wiki/Latent_semantic_analysis http://en.wikipedia.org/wiki/Latent_semantic_analysis