11. The one or more computer-storage media of claim 9 , wherein the information metric is calculated at least by determining whether the terms that comprise the atom have previously been searched by inspecting query logs.
9. One or more hardware computer-storage media storing computer-useable instructions that, when used by a computing device, cause the computing device to perform a method for populating one or more search indexes with atoms identified in a plurality of documents, the method comprising: identifying a plurality of atoms from a first document of a plurality of documents that are to be indexed; classifying each of the plurality of atoms as one or more of a unigram, an n-gram, or an n-tuple; computing an information metric for each of the plurality of atoms in relation to the first document, wherein the information metric for a first atom identified in the first document represents a pre-computed ranking used during a search query for the first atom as to how useful the first atom is in relation to the first document in resolving the search query having the first atom; determining whether the information metric for each of the plurality of atoms meets a predetermined threshold, wherein the atoms that meet the predetermined threshold are those that are most relevant in relation to the first document; discarding the atoms that do not meet the predetermined threshold; and incorporating the atoms that meet the predetermined threshold in relation to the first document into the one or more search indexes, wherein identifying the first document from the one or more search indexes as relevant for the search query is based on a pruning algorithm that computes a preliminary score for the first document to select the first document based on the preliminary score, the first document is selected from a set of documents indexed in the one or more search indexes, wherein the preliminary score is computed using the information metric pre-computed for each atom/document pair and a simplified scoring function that approximates a final ranking algorithm utilized in identifying the first document as relevant for the search query.