The AOL Instant Messenger (AIM) is a free instant messaging computer program, published by AOL, which uses the OSCAR instant messaging protocol and the TOC protocol. The most recent software version is AIM 5.2, released in June of 2003. AOL has described this technology as a means of "immediate cross-Internet communication". [1]

It allows users to communicate instantly through text to their "buddies" around the world, provided they have the AIM software. AIM has 100 million users, with a large proportion using Internet slang. Advocates claim that it's easy to locate these users by visiting chatrooms that AOL has set up solely for those purposes. Chat topics range from *NSYNC to current affairs. AOL also has a member directory where AIM users can locate others online who share their interests.

Since version 2.0, AIM has included person-to-person text messaging, chatroom messaging, and the ability to share files peer-to-peer with your buddies. Unlike Napster, and other peer-to-peer software, there is no directory of files, you only transfer files to one another as one would in an email. Somewhere in the 4.x series, the AIM client for Microsoft Windows added the ability to play games against one another. Recent (4.3 and later) versions of the client software store your contact information on AOL's servers, so you can talk to up to 200 of your buddies from any computer with Internet access. Stand-alone official AIM client software is available for free (but is not free software in the GNU sense) for Microsoft Windows, Mac OS, Linux, Windows CE, and Palm OS. However, some users stay on the 3.0 series because the software license agreement for 4.0 and later clients includes a clause prohibiting the user from ever using a third-party client program.

There is also a client called AIM Express implemented as an applet for the Java platform that runs in your web browser. AIM Express does not have all the features of stand-alone AIM clients (such as file transfer, buddy icons, and away messages), but it still allows the basic functions of person-to-person text messaging.

The standard protocol that AIM clients use to communicate is called OSCAR. AIM Express uses another protocol called TOC. TOC has also been made available to the public, in an attempt to throw a bone to third-party client developers and lure them away from OSCAR. This scheme has not been entirely successful. Because AOL wants to be able to serve advertisements to users, AOL has continually changed the details of the OSCAR protocol to keep third-party clients such as Trillian from working properly. This has resulted in a cat-and-mouse game between AOL and the client developers.

AIM software is the first to use online video streaming advertisements, via the Eyewonder protocol.

Alternate clients

While there are a variety of alternate single protocol clients, one should also consider using a multi-protocol client if the need arises to use AIM simultaneously with another chat service. open source options include miranda im for Windows and gaim for Linux. Commercial alternatives are Trillain for Windows and Fire for the Mac.

External links and additional Resources

To download AIM, or find out more information go to: Online versions of AIM are available at A third-party developer, under the handle "trogdor" has written a component for Delphi that connects to the AIM service as a 5.2 client. It is availabe for free at

545 Studios (which is not affilliated with AOL) has made a 3rd party program called AIMutation ($3.95 to purchase) that overlays additional features atop AIM (version 5 or later) without consuming gobs of resources. More information at

JDennis (which is not affilliated with AOL) has made a 3rd party program called DeadAIM ($4.99 to purchase), that modifies AIM to include many new features. The current version and more information is available at You can download an older freeware version of this program at, click on DeadAim and then you can download the version DeadAIM 3.2.8.

MyAIM, a free plugin for AIM 4.8, transparently adds many new features most notably transparency, cloning, and chat logging. Future versions of MyAIM are planned to support AIM versions 5 and later. More information at

To log in to AIM through AIM Express, go to

Another version of AIM Express can be found at