Microsoft might have killed off its Messenger service in favor of Skype recently, but back in 1999 it was the centerpiece of a heated war between the software giant and AOL. At the time, Microsoft had just introduced its MSN Messenger Service as a direct rival to AOL's popular AIM instant messenger. David Auerbach, a former Microsoft engineer who worked directly on MSN Messenger, recounts his unusual role in a chat war with AOL. Auerbach had reverse-engineered AOL's chat protocol to allow MSN Messenger to sign into AIM, a process that AOL wasn't happy with when Microsoft first released its instant messaging client in July 1999.

AOL kept blocking MSN Messenger from accessing AIM, and Auerbach persisted at Microsoft by creating new ways to work around the blocks put in place. The battle resulted in AOL using a security bug in its own AIM software to prevent Microsoft from accessing its AIM service, a move that forced Auerbach and his coworkers to give up on any dreams of interoperability between AIM and MSN Messenger, but not before an unknown Microsoft employee posed as software consultant to try and get security experts to detail the AOL flaw. Auerbach's recount is a fascinating look at an early war over instant messaging before it became a daily part of the internet.