1. A computer-implemented method for ranking candidate documents in response to a search query, comprising steps of: creating, by at least a first processor, an index of a plurality of documents in a corpus; calculating a junk score for at least a first document in the corpus, wherein calculating the junk score comprises: using a first candidate histogram for the first document in the corpus, wherein the first candidate histogram is specific to the first document; and using a junk profile, wherein the junk profile comprises: a first reference histogram for a first known junk document, wherein the first reference histogram is specific to the first known junk document and is based on a first junk variable; and comparing the first candidate histogram to the first reference histogram; receiving a search query; identifying, based on the search query and the index, candidate documents from the plurality of documents in the corpus, wherein the candidate documents include at least the first document; ranking the candidate documents.