AOL Instant Messenger lost 64% of its users in 2011

"Before there was Facebook, Twitter, or Pinterest, there was AOL Instant Messenger.
In fact, you could argue Facebook was conceived on AIM.
My how times have changed.
Between January 2011 and January 2012, AOL Instant Messenger usage – on AIM.com and in the AIM app – declined 64%, from 12 million users to just 4 million."

Source:  Business Insider, 3rd April 2012