The iconic app was a staple for anyone who loved the Internet in the 90's and early 00's.
In a post on Tumblr, Oath VP of communications Michael Albers writes:
AIM tapped into new digital technologies and ignited a cultural shift, but the way in which we communicate with each other has profoundly changed. As a result we’ve made the decision that we will be discontinuing AIM effective December 15, 2017. We are more excited than ever to continue building the next generation of iconic brands and life-changing products for users around the world.
It's not yet clear what will replace AIM. Users will be able to use the service until December 15, and email services will continue as normal.