AOL Instant Messenger is expected to be available for Lycos's 32 million registered users in December, allowing them to communicate with each other as well as with the 45 million registered AIM users.
The recruitment of Lycos will likely intensify the battle over instant messaging on at least two fronts. For AOL, Lycos is an important ally in its fight against Microsoft and, to a lesser degree, Yahoo, over which version of the important communications software is used. For Lycos, the move allows the portal to catch up with Yahoo by adding a critical feature in a market where all rivals must match each other's services to stay competitive.
The IM battle erupted this summer after Microsoft released MSN Messenger, a rival to AOL's messaging software, in hopes of chipping away at America Online's lead in this area. The move particularly angered AOL because Microsoft included a critical feature that allowed those using its messenger software to communicate with those using AIM.
In response, AOL altered its systems to block Microsoft's attempts to connect the two messaging services.
The battle quickly escalated, prompting other competing messenger services to form alliances against AOL, which they accused of violating the spirit of the wide-open Web by blocking outside communication. The online giant enlisted its own allies, most notably Apple Computer.
"This agreement with Lycos, the Internet's fastest growing portal, is a great way for us to continue the momentum of the world's leading and most exciting instant messaging community," AOL president Bob Pittman said in a statement.
Rather than drive a deeper wedge between Microsoft and AOL, the Lycos deal could put added pressure on Microsoft to enter a similar arrangement. At least one analyst said AOL may be receptive to such a move.
"AOL is saying that rather than [letting people] hack into its system, it wants to work out bilateral agreements" for sharing its IM technology, said Philip Leigh, an analyst with Raymond James. "I don't think it hurts AOL to have people from Microsoft [accessing the AIM servers] any more than people from EarthLink or MindSpring" or other services it has cut deals with.
Microsoft expressed disappointment in the announcement and reiterated calls for AOL to open its system to all comers.
"This once again shows that AOL is not listening to consumer demands for interoperability," said Tricia Fahey, a Microsoft spokeswoman.
Fahey said Microsoft will continue to work with industry groups like the Internet Engineering Task Force and its Instant Messaging and Presence Protocol project to create standards that will work across platforms.
"We haven't changed focus," she said. "We hope that AOL joins with the rest of the industry so that consumers can choose between products and still communicate with everyone else."
Under today's agreement, Lycos will promote a cobranded version of the AIM software in its registration process while its own customized version of AIM is developed.
"We are pleased to embrace the AIM instant messaging community and to allow our users to easily communicate with what has become the largest IM environment in the world," Lycos chief executive Bob Davis said in a statement.
News.com's Evan Hansen contributed to this report.