Abstract: A method of compressing short text messages, comprising: generating an index code comprising an association of keywords in the text messages with indices, the index code is logically divided into segments of variable size, each segment comprising at least one bucket, being a constant range of indices; adjusting the index code according to a natural keyword frequency distribution and to statistical analysis of the text messages; associating short indices with frequent keywords in the text messages; converting the text messages into compressed text messages in which at least some of the keywords are replaced by the associated indices; and updating the association between the indices and the keywords, updating the segments, and updating the updating frequency in respect to a usage keyword frequency distribution and temporal changes thereof