How AOL Instant Messenger Works

Instant messaging (IM) epitomizes communication in the internet age, and people from all walks of life are now proficient at it. But there was a time, not so long ago, when only a few trailblazing programs had introduced this fast and free technology to mainstream audiences. AOL Instant Messenger is remembered as one of those programs.

What's IM exactly? By downloading a small program on their computer, IM users can send and receive short text messages over the internet. IMs are different than e-mails, because they enable a real-time conversation between two or more people. When I type an IM and press send, the other people in the conversation see that message immediately and can reply within seconds.

AOL Instant Messenger was discontinued in late 2017, but the service still has many fans. So, let's wax nostalgic by revisiting this technology and how it worked. In this article, we'll explain how AIM users enjoyed the software's basic and advanced features.

AOL Instant Messenger: A Brief History

AOL Instant Messenger (AIM) was one of the most popular IM programs. It's also one of the oldest. The first version of AIM was released in 1997, one year after the release of ICQ, the very first publicly available IM client. At its peak, AIM boasted 33 million unique users every month. During peak hours, over 6 million people were logged on to AIM at the same time [source: AOL].

AIM evolved over the years to offer an expanding list of services. Besides sending simple text messages, users could share photos, videos, music, and other files. They could even use the AIM software to make free internet phone and video calls.

Although the service had been a significant part of internet culture in the late 1990s and early 2000s, by the time it was discontinued in 2017, it was a relic in the instant messaging market. The dynamic, mobile-first competition established by Facebook Messenger and WhatsApp had taken over.

Using AIM

To start using AOL Instant Messenger, you needed to sign up for a screen name. A screen name was like an e-mail address for IM. If a person wanted to send you an IM, they needed to know your screen name. Here's how you'd sign up for an AIM screen name and set up a profile:

Go to AOL Instant Messenger and click on the link that says "Get a screen name."
Select "Create an account" and click continue.
Type in your desired screen name and a password.
Answer the security questions and click continue.
If your screen name was already taken, you'd be prompted to enter a new one. AIM would help you find an available screen name based on your preferences.
Once you found an available screen name, you'd be sent a confirmation e-mail with a link to open your new account.

Once you had a screen name, you needed to download the AIM software client. The first time you opened the AIM software, it would ask if you want to search your existing e-mail contacts for buddies. "Buddies" is an AIM term for contacts. AIM would automatically search your Yahoo! Mail, Hotmail and Microsoft Outlook accounts for contacts who also had AIM screen names. AIM would then give you the option of adding these screen names to your Buddy List. Your Buddy List was the organized list of IM contacts stored in your account.

When you'd open AIM, you'd see a main window featuring your Buddy List broken down into different groups. The default Buddy List groups were Buddies, Family, Co-Workers and AIM Bots (automated Buddies for movie times, stock quotes, et cetera). You could add new groups of your own by going to the Edit menu and choosing "Add Group."

Finding AIM Clients

When you wanted to add a new contact to one of these groups, you'd go to the Edit menu and select "Add Buddy." You'd then be asked to choose a group for the contact. You could also enter more information about the person, including their e-mail address and mobile phone number.

Your Buddy List told you which of your contacts were online and which were offline. The contacts that were online were listed under their group headings. Those that were offline were listed at the bottom in a group titled "Offline."

Sending Instant Messages

The easiest way to send an IM was to send a message to someone on your Buddy List. There were two basic ways to do that:

Highlight the contact's screen name in the Buddy List and click the IM button at the bottom of the window.
Double-click on the buddy's name and an IM window would automatically open.

If you wanted to send an IM to a person not on your Buddy List, you'd go to the AIM menu in the main window and select "New IM." You'd then be prompted to enter the screen name of the person you wished to contact.

Once you'd opened an IM window, it was easy to send a message. You'd simply type your message into the white text box near the bottom of the IM window. When you were finished typing, you'd either hit the enter key on your keyboard or click the "send" button in the bottom right corner of the IM window. The text that you entered would appear in the top half of the IM window. When your buddy replied, you'd see his or her response under your message like a conversation.

Saving and Blocking AIM Users

You could save IM conversations from the File menu by clicking on "Save Window." You could also open the conversation later and pick up where you left off.

AIM would notify you with an alert tone when you received a new IM. If someone IM'ed you who wasn't on your Buddy List, you'd get a message saying that "[screen name] has sent you an IM. Do you want to read it?" You always had the option to ignore an IM and even to block a particular screen name from ever sending you an IM again.

AIM's Chat Service

If you wanted to IM several people at the same time, you could invite all the participants to join a temporary chat room. Here's how you'd set up a chat:

Go to the AIM menu in the main window.
Roll over "Chat" and click on "Buddy Chat."
Enter the screen names of all of the people you wanted to invite to the chat.
Your buddies would receive an invitation, which they could accept or deny.

A chat room worked the same as normal IM. To send a message to the group, you'd type it into the text box and press the enter key or click send.

Later Features for AIM

One of the later features for AIM was the ability to send IMs to cell phones as text messages. To do this, you'd need to know the cell phone number of the person you wished to send it to.

There was even a new feature called IM forwarding that forwarded IMs to your cell phone when you were away from your computer. You could activate IM forwarding by going into the main Edit menu and clicking on Settings. In the Settings window, you'd choose Mobile and register your cell phone for IM forwarding. You could even reply to forwarded IMs with text messages from your cell phone.

AIM Phoneline Services

AIM was capitalizing on the popularity of Voice Over IP (VoIP) telephony by offering free internet phone calls to other AIM users. To make internet phone calls through AIM, you'd need a headset with a built-in microphone or a computer with speakers and a microphone.

AIM Call Out was another VoIP service, and this one was similar to Skype. You could call any phone number directly from AIM, but you'd be charged by the minute.

AIM File-Sharing

File-sharing was another useful feature of AIM. You could easily send individual files or whole file folders to any other AIM user. Here's how it worked:

Double-click on a buddy or open a new IM window through the AIM menu.
Click on the "Send Files" button at the bottom of the IM window and choose "Send File" or "Send Folder."
This would open up a window asking you to select the file or folder from your computer.
The recipient could choose to accept or deny the file transfer.

For sharing photos, AIM 6.5 had a special "Pictures" button at the bottom of the IM window. This feature let you drag and drop photos into the IM window. The photos would be resized and sent instantly to the recipient as individual pics or a slideshow.

With AIM 6.5, AOL had also expanded social networking options for users. You could create a public or private profile page on which to share photos, hobbies, and links. These AIM Profile pages included links to your buddies' pages as well. You could access your profile page by going to the AIM menu and choosing "Open My Profile."

AIM Express and Other Products

On an increasing basis, computer users are depending on instant messaging to reach friends, even when they're not at home. AIM Express allowed users to send IMs to friends without downloading or running any software. AIM Express ran in any Web browser and was convenient for users who couldn't access AIM.

Friends could talk to friends from any location as long as they were at a computer that has internet access. They could use it at home, school, or work. AIM Express worked just like the software version of AIM. The application loaded your entire Buddy List. Any new buddies or groups you added would automatically be added to your desktop version the next time you logged on. You could also access AOL Mail through two e-mail icons at the bottom of the window.

AIM Share

AIM Share was another web service that let you send a link or broadcast a message to all of your buddies at once. You could either log onto the AIM Share website or add a special AIM Share button to your browser toolbar.

When you found a cool website, you could click the AIM Share button and AIM would create a message featuring the site's URL. By typing a quick description and pressing "Share", you'd send to the link to everyone on your Buddy List.

AIM Expressions and AIM Tunes

AIM Expressions was a newer site for managing your buddy icons and wallpaper. A buddy icon was the small image that accompanied all of your outgoing IMs as well as your buddy profile. Wallpaper was the background to your buddy icon.

In the My Personality box at the top of the AIM Expressions page were your current settings. You could click the Change buttons to browse a list of dozens of buddy icons and wallpapers. You could also type "buddy icon" into Google and find hundreds of sites for downloading customized buddy icons.

AIM Tunes, meanwhile, was a later application that allowed any two AIM users to listen to each other's music for free. The service couldn't, however, stream music protected by DRM (digital rights management), which included most of the MP3s sold on sites like iTunes and Napster [source: YouTube].

AIM Security Holes

Starting in January 2002, there were several well-publicized security holes reported in AOL Instant Messenger [source: ZDNet]. The holes made it possible for a hacker to take over a user's computer by infecting it with malicious code, called a worm. AOL closed most of these security holes by adding special filters to their AIM servers. According to an article from Wired News, security holes continued to be an issue for AIM, leaving room for a potentially devastating, widespread worm attack.

AIM Applications

According to a 2004 study by the Pew Internet & American Life Project, 11 million Americans used IM at work [source: Pew Internet & American Life Project]. While some office workers undoubtedly used IM to chat with friends, many others tapped into the technology as a powerful professional collaboration tool.

With this in mind, AIM released AIM Pro, a free IM tool that was designed to meet the communication needs of the modern office. Here were some of the key features of AIM Pro:

Desktop sharing - AIM Pro was powered by WebEx, a conferencing company. Desktop sharing was a powerful Web conferencing tool that allows you to show the contents of your computer screen to anyone logged into the conference.
Videoconferencing - This feature was similar to video calls on AIM 6.5. You could add video capability to any chat session between AIM users.
File-sharing - You could send important documents to colleagues instantly without worrying about exceeding maximum attachment sizes on e-mails.
E-mail - AIM Pro integrated with Microsoft Outlook so you could send, receive, and manage all e-mails and IMs from one interface.
Calendar - AIM Pro had a built-in calendar program that also integrated with Microsoft Outlook to update you on important meetings and appointments directly in the IM window.
Security - AIM Pro relied on the secure WebEx conferencing infrastructure to encrypt and safeguard information that traveled across the network.

Unfortunately, all of these services folded when the parent company discontinued AIM in December of 2017.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.

How AOL Instant Messenger Worked