USA.net will transition 20,000 United employees from Hewlett-Packard's OpenMail software to USA.net's Web messaging platform and will take responsibility for managing and maintaining the system. The migration will begin in the first quarter of 2000. Financial terms of the agreement, revealed mid-November, were not disclosed.

The United contract is the largest enterprise deal USA.net has signed, says USA.net CEO John Street. To date, only about 1 million of USA.net's 13.5 million subscribers are businesses.

Companies are turning to outsourced messaging services as a way of reigning in the spiraling costs of supporting end users. According to Creative Networks Inc., companies spend up to $386 per E-mail user per year in IT labor costs alone.

United expects that users will be able to be more productive with a Web E-mail system. "We wanted employees to have access to E-mail from any place at any time," says Nirup Krishnamurthy, United's director of business systems development. United says it's also considering working with USA.net to improve its customer service. Krishnamurthy doesn't know exactly what form this application will take, but he says that United could, for example, use USA.net messaging to alert customers to flight delays.

Companies are increasingly looking to their messaging platforms as a way of interacting with their customers. Earlier this month, American Express Co. launched a secure messaging platform that card holders can use to send and receive information about their credit-card accounts. Customers receive a password-protected mailbox on the American Express Web site, so queries and responses with confidential account data don't have to cross the Internet. The service is based on Tumbleweed Communications Inc.'s Integrated Messaging Exchange platform.