Osterman said archiving systems such as AXS-One are "pretty high-end" products for large companies with e-mail indexes that bulge out to "Google-like sizes." Other products in that category include Symantec Corp.'s Enterprise Vault and EMC Corp.'s Documentum line, he added.

A less costly alternative, Osterman said, is adding search and retrieval software from vendors such as Mimosa Systems Inc. and Lucid8 LLC to existing e-mail servers. "Lots of companies, especially those with a reasonable number of e-mail users, can get by just with search and extraction tools," he said. "If you've got 100,000 e-mail users, you might want to go with an archiving tool."

A third route is to swap out one of the first-tier mail servers for a less expensive product with stronger built-in search and storage features. That's what the city of Marshalltown, Iowa, did in December, when it moved from Novell Inc.'s GroupWise to a Linux-based e-mail server from PostPath Inc.

PostPath CEO Duncan Greatwood said the Mountain View, Calif.-based start-up's software is fully compatible with Microsoft Corp.'s Exchange Server. But PostPath uses the Linux file system to store messages more efficiently, enabling users to have "bottomless mailboxes," Greatwood claimed. He also said that users can more easily search for messages in PostPath's software than in Exchange.

William Lawyer, Marshalltown's information systems coordinator, agreed that messages stored PostPath can be easily managed and searched. "We don't have a monolithic database with all sorts of post office files to deal with," Lawyer said. "PostPath just stores each mail as an individual file."