AOL has upgraded AIM, its popular IM (instant messaging) service with new features, such as the ability to send messages to offline users and to store IM sessions in a PC.

In AIM 6.0, AOL also doubled the number of contacts a user can have in their 'buddy' list to 1,000 people, AOL plans to announce today.

AOL is involved in a scalding hot competition in the consumer IM market with rivals Microsoft and Yahoo, which recently established a basic level of interoperability between their IM networks.

AOL, Microsoft and Yahoo operate the three most popular consumer IM networks, but AIM users can't communicate with Microsoft and Yahoo users because each network operates with proprietary communication protocols. Microsoft's Windows Live Messenger leads with 29 percent of users worldwide, followed by AIM with 27 percent and Yahoo Messenger with 21 percent, according to the Radicati Group.

AOL is working with Google to link AIM with the Google Talk IM service. AIM already has interoperability with other IM platforms, such as Apple's iChat, Reuters's system and AOL's own ICQ, a sister IM network to AIM.

As one of the most popular online-communication tools, IM has evolved from offering users only the ability to exchange text messages in real time to providing an ever-expanding suite of services, such as internet telephony, video chats, games and integration with email systems and other online services. Because IM services are so popular, they are also attractive vehicles for delivering online advertising.

AOL will actively encourage all of its AIM users to upgrade to 6.0, since two-thirds of them are on AIM 5.9 and the rest on a more advanced version called Triton, launched last year, said Ann Santorios, AIM's director of product management. AIM has about 70 million active users worldwide, 42 million of them in the US, she said.

AIM 6.0 has been built using Triton's code base and software architecture, and will thus retain Triton's communication features, but with a redesigned user interface, she said. "This is Triton with a facelift," she said.

The new offline-messaging feature lets users send messages to people on their 'buddy' list who aren't logged on at the time. They will receive the messages as soon as they sign on to AIM. Meanwhile, with the conversation logging option, users will be able to save text chats as HTML files on their computers.

Other enhancements in 6.0 include:

  • A new 'dashboard' intended to make it easier for users to access existing mobile features, such as setting up mobile alerts and IM forwarding
  • Deeper integration with the new AIM Pages blogging and social-networking service, including one-click access from the AIM interface
  • A redesigned AIM Today welcome web page, expected to launch next week, with access to users' webmail accounts from AOL, Google's Gmail and Yahoo's Mail Plus;
  • A new notification service that sends RSS alerts whenever an AIM user adds new content to accounts on services such as Yahoo's Flickr and, Six Apart's LiveJournal, Google's YouTube and Blogger and News Corp's;
  • Single sign-on to a variety of AIM-related services, such as the AIM Mail webmail service.

While not revolutionary, AIM 6.0 is a strong update, with enhancements that might be compelling enough to motivate users to upgrade, said analyst Michael Osterman of Osterman Research. Sending offline messages and storing IM sessions seem like useful features, he said.

The upgrade may be particularly interesting for AIM 5.9 users, who can get the best Triton features and a new set of enhancements, Osterman said. Triton's relatively low adoption is due to several reasons, including misgivings about its user interface and users' perception that Triton lacks must-have new features, Osterman said.

AIM 6.0, which requires Windows XP or Windows 2000, can be downloaded for free here.