1. A system comprising: a storage device storing first textual data, uncompressed second textual data, compressed third textual data, and a dictionary, the dictionary having a plurality of keys, each key associated with an identifier, the keys comprising: a plurality of static word or phrase keys, each static word or phrase key listing one or more unchanging words in a particular order; and, a plurality of dynamic phrase keys, each dynamic phrase key listing a plurality of words and one or more placeholders in a particular order, each placeholder denoting a place where a word or phrase other than the words of the dynamic phrase key is to be inserted; a dictionary-constructing mechanism to generate the dictionary from the first textual data; a compression mechanism to compress the uncompressed second textual data to yield the compressed third textual data using the dictionary; and, a decompression mechanism to decompress the compressed third textual data to yield the uncompressed second textual data using the dictionary.