Conpherence is a group messaging application integrated into Phabricator. Message one-on-one or with a group of people, name your room, and keep a history of everything in one place. Reply via email, on the web, or on your mobile device.
Conpherence supports Remarkup that makes it easy to link to Maniphest tasks and code reviews, share code snippets, format tables, and share memes. Conpherence even has a persistent chat sidebar built-in, so you don't need to keep another tab open.