Discord, used by suspect accused of leaking classified docs, has become more popular with extremists

Discord, the social media platform on which U.S. classified documents appearing to pertain to the Ukraine war and other parts of the world were leaked over the last several months, is one of a number of platforms that have become popular with far-right extremists, experts say.

In its infancy, Discord was built by founders Jason Citron and Stan Vishnevskiy to help people around the world chat while playing video games online. Launched in 2015, the platform today is home to 150 million active users around the world with communities of interest that extend into education, music, tech, and science.

Discord is organized by servers; a Discord user can create their own server or can join another server. Servers are comprised of multiple text channels where users can communicate in real-time text, voice, or video.

Unlike other popular social media platforms like Twitter or Facebook, Discord is often referred to as a closed platform. While large public forums do exist on the platform, other communities are closed and require an invitation to join.

Last year, the New York attorney general's office announced it was investigating tech platforms including Discord in connection with the mass shooting in Buffalo that killed 10 people.

In a bulletin published after the Buffalo shooting, the NYPD said that platforms like Discord have become popular social media alternatives for far-right extremists due to minimal content moderation, as opposed to more mainstream social media platforms.

Discord and platforms like it "underscores that an online connection to an extremist culture and ideology through social media, online gaming platforms, or anonymous message boards like 4chan, can be equally effective in mobilizing individuals to violence as connections to real-world groups," the bulletin also said.

Users on Discord can sign up using only minimal personal information that does not need to be verified. Users are only required to enter a working email address.

Adam Scott Wandt, the vice president for technology and assistant professor of public privacy at John Jay College of Criminal Justice, told ABC News that the way Discord is set up allows people to post things they wouldn't post on mainstream platforms like Facebook or Twitter.

"When people get access to anonymity, they do different things they wouldn't necessarily do," Wandt said.

However, Wandt said that law enforcement is still able to track users down through their IP address.

Wandt said that while the user base for Discord has grown over the years, the majority of users are under the age of 35.

While Discord and other messaging platforms have been scrutinized for their content moderation and privacy rules, the Discord platform is mostly used by gamers, crypto enthusiasts and younger people to chat and interact. It has become more popular over the years, experts said.

Following the shooting in Buffalo, New York, Discord said in a statement that it was implementing measures to prevent the spread of content related to attacks, and would also remove accounts of malicious actors.

The platform also now has a "safety tab" on its interface where it provides information on how to report content to Discord and how to help teenagers "stay safe" on the platform.

But some experts say the minimal content moderation rules on Discord are still a problem.

"In these forums you can kind of act as you wish, and it just depends on the moderators of either the subsection or the overall site to take action, and that's highly variable," Thomas Holt, director and professor in the School of Criminal Justice at Michigan State University, previously told ABC News.

"Discord across the board has to do a better job with moderation of their platform," Wandt echoed. "I recognize that times are hard to moderate private chat rooms, but ultimately Discord has to do better overall."