Due to the current situation, there are more and more collaborations
happening online instead. and now you can see Wikimedia-related discussion
groups in Slack, Discord, Telegram, Facebook, and many more. Besides being
scattered and inaccessible to people who don't have accounts in those
platforms (for privacy reasons for example), these platforms use
proprietary and closed-source software, are outside Wikimedia
infrastructure and some harvest our personal data for profit.
IRC on freenode is a good alternative but it lacks basic functionalities of
a modern chat platform. So we created Wikimedia Chat, a mattermost instance
in Wikimedia Cloud. Compared to IRC, you have:
* Ability to scrollback and read messages when you were offline
* Push notification and email notification
* You don't need to get a cloak to hide your IP from others
* Proper support for sharing media
* Two factor authentication
* A proper mobile app support
* Ability to add custom emojis (yes, it's extremely important)
* Profile pictures
* Ability to ping everyone with @here
* much much more.
You can use Wikimedia Chat by going to https://chat.wmcloud.org
, anyone can
make an account. This is part of Wikimedia Social suite , the oher
similar project is "Wikimedia Meet". 
* This is done in my volunteer capacity and has been maintained by a group
of volunteers. If you're willing to join the team (either technical or
enforcing CoC, kicking out spammers, other daily work), drop me a message.
* As a result, all messages older than 90 days get automatically deleted.
* As a Wikimedia Cloud project, all of discussions, private and public are
covered by Code of conduct in technical spaces: https://w.wiki/AK$
Hope that would be useful for you, if you encounter any technical issues,
file a bug in the phabricator.