Stepping up its effort to loosen America Online Inc.'s grip on the fast- growing online instant messaging market, Microsoft is aligning itself with three rival providers.
Microsoft planned to announce Wednesday that the three services - Prodigy, Tribal Voice and PeopleLink - have agreed to give their users the ability to instantly exchange notes with the 1.3 million users of the Microsoft Network's instant message service.
The move increases the pressure on AOL, which is refusing to allow MSN's subscribers to communicate by instant messaging with the 43 million users of its service.
Instant messaging offers Internet users the ability to exchange notes that immediately pop up on the recipient's computer screen.
In the past month, AOL has repeatedly counter- attacked Microsoft's attempt to link its rival product with AOL's service. AOL, for its part, has allied with three other Internet service providers to enable their users easy access to AOL's Instant Messenger service.