"Just as we have in the past, we continue to block anyone who attempts to use the AOL infrastructure in an unauthorized way regardless of whether those infringements involve new products or efforts like spamming, hacking, or password stealing," said AOL spokeswoman Ann Brackbill.
Microsoft yesterday unveiled its MSN Messenger service, which has an added feature that allows its users to communicate with AOL Instant Messenger users. An updated beta version of Yahoo Messenger also allows users to communicate with AOL screen names.
AOL yesterday criticized Microsoft's MSN Messenger, charging that it poses a security risk to AOL users. When new MSN Messenger users want to import their AOL Buddy Lists, it asks them to type in their passwords. AOL said Microsoft was "goading" users to reveal their passwords and compared the practice to what hackers do. In response, Microsoft denied there was a security risk because the company cannot access the passwords.
Users of Microsoft and Yahoo's services were able to send instant messages to AOL screen names yesterday. But this morning, a number of CNET News.com readers, including members of the Internet Engineering Task Force charged with seeking a standard protocol, reported that they were unable to send messages from MSN Messenger software to users of AOL Instant Messenger, despite having been able to do so yesterday.
The readers said that attempts to send messages from Microsoft's software to AOL Instant Messenger users results in an "incorrect password/login" error. Some said the same is true for Yahoo Messenger, Yahoo's second-generation instant messaging client, which is currently in beta.
Brian Park, senior producer for Yahoo Messenger, said the protocols used to build interoperability with AOL Instant Messenger are not working anymore.
"They were working last night, and they are not working today," he said. "I'm assuming that AOL made a change to their protocols."
A Microsoft spokesman called the act "unfortunate" and against consumer demands for open instant messaging platforms. "They are more focused on maintaining their own situation than what's right for their consumers," he said about AOL.
AOL's Brackbill disagreed. "This has nothing to do with being unreceptive to consumers," she said. "In our view, Microsoft's just violated the cardinal rule of the Internet by asking our users their screen names."
AOL's popular Instant Messenger service allows users to establish a Buddy List of users with whom they can communicate in real time. AOL has attracted millions of users to its Buddy List network, which it considers a valuable platform to serve advertising and promote its subscription service. Much of the Buddy List's traffic stems from nonmembers who can download the communication software onto their computers.
Microsoft has said it supports establishing an open standard for all instant messaging services to communicate with one another. But the client currently does not allow communication with Yahoo Messenger.
AOL is opposed to the proposed standard, because it wants to protect its existing market dominance, analysts said. AOL also owns ICQ, another popular instant messaging service that the company has turned into a "desktop communications portal." As of June, ICQ had 35 million registrations.