Snikket is a new XMPP/Jabber-based decentralised FOSS messenger service. You can follow at:
The official website is https://snikket.org
It aims to make XMPP into a more viable alternative to Whatsapp etc by providing consistency in design and terminology.
(It's sort of how Mastodon made ActivityPub more mainstream, by using consistency to make it clear the instances are part of one network.)
Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.