We know that this is going to bring tears to the eyes of many (just kidding), but a piece of online history will be going away for good on December 15. Verizon Oath, which owns the AOL and Yahoo brands, announced that AOL Instant Messenger (AIM) will be shut down on that date.
When AIM was first launched in 1997 as a Windows application, it became very popular for online chatting and even defined many of the design themes still in use for messaging. AIM became accessible to Mac users through Apple's iChat, which provided AIM users with a way to hit both services with one app. Through that connection, it became possible for Mac and Windows users to chat cross-platform.
macOS High Sierra removed support for AIM last month. The death knell for AIM has been ringing for several years now, with Facebook Messenger, Google, Slack, WhatsApp, and other multi-platform messaging services eclipsing the stodgy AIM. Oath made the impending closure of AIM official through posts on Twitter and Tumblr, without announcing a replacement or any way to archive messages sent in the past.