5. A computer system for processing queries, comprising: memory; one or more processors; and one or more programs stored in the memory and configured for execution by the one or more processors, the one or more programs including: instructions for receiving, from a client system distinct from the search engine server system, a search query having one or more query terms; instructions for identifying a set of search result documents in accordance with the search query; instructions for generating a content snippet corresponding to content in a respective document of the identified set of search result documents, the content snippet associated with at least one query term of the one or more query terms in the search query; and instructions for returning a response to the client system that includes information identifying at least the respective search result document and including the content snippet of the respective search result document; wherein the instructions for generating the content snippet comprises: instructions for receiving a set of first token identifiers, comprising compressed content of the respective search result document, from a compressed document repository; instructions for performing a first decompression operation by applying one or more first mappings to the set of first token identifiers to provide a set of second token identifiers; and instructions for performing a second decompression operation by applying a second mapping to the set of second token identifiers to recover uncompressed content comprising a portion of the respective document wherein the first decompression operation produces a respective second token identifier for each first token identifier, the set of second token identifiers has a same number of distinct token identifiers as the first set of token identifiers, and the second decompression operation produces a respective uncompressed content item for each second token identifiers; and wherein each first token identifier comprises an M bit integer value, and each second token identifier comprises an N bit integer value, N and M are positive integers and N is greater than M.
6. The computer system of claim 5 , further comprising instructions for deriving relevancy scores for at least a subset of the identified set of search result documents, and instructions for selecting the respective document based on having a high relevancy score.