(AP) – AOL announced Friday that it is discontinuing its pioneering Instant Messenger chat platform after 20 years of service.

An article on AOL’s website posted Friday says AOL Instant Messenger will be discontinued on Dec. 15. In a blog post , a spokesman for AOL’s parent company explained the platform’s demise as the casualty of the evolving way people communicate.

“AIM tapped into new digital technologies and ignited a cultural shift, but the way in which we communicate with each other has profoundly changed,” wrote Michael Albers, vice president of communications at Oath.

The program will still function until Dec. 15 After that date, users won’t be able to sign in and all data will be deleted. AOL says people with an aim.com email address will still be able to use it.

Launched in 1997, AOL Instant Messenger was at the forefront of what was called at the time the biggest trend in online communication since email.

The platform, which provided instant access to friends and contacts on a user’s “buddy list,” was wildly popular for the first few years after its launch. It claimed more than 100 million registered users in 2001.

AOL was fiercely protective of its dominance in the instant messaging market. It fended off rivals, including Microsoft, by blocking their messaging platforms from communicating with AOL users. Its actions prompted a coalition of rivals to complain to the federal government ahead of AOL’s ill-fated merger with Time Warner that was completed in 2001.

Its popularity as a communication tool waned amid the rise of text messaging, Google Chat and social networking sites.

Despite the decline in usage, the announcement Friday made the platform a trending topic online and revealed an outpouring of nostalgia. Some users posted images of the AIM’s famous “running man” logo outfitted with wings and a halo. Others reminisced.

In his post, Albers noted the strong affinity many feel for the messaging platform and its place in the evolution of communication.

“In the late 1990s, the world had never seen anything like it,” he wrote.