Most communication for the sim takes place on Discord. You can join the group at discord.me/USSJoshuaNorton. We can be a chatty bunch, so it's highly recommended you leave the notifications for the server to @mentions only, and then consider turning on all notifications for the tags channel. As we have people in multiple timezones, please make sure that you make use of Do Not Disturb mode on your phone if you have Discord installed there.
Discord is a free text and voice chat service that is targeted at video gamers, but has been embraced by a number of communities. They have clients for Android, iOS, Windows, OS X, and 64 bit Linux distros, or you can use their web client.
If you can't, or don't want to, use Discord for some reason, some of the crew do also use other chat programs such at telegram, signal, yahoo, skype, etc. and sometimes even list them in their player information within the Nova. Also, there is a PM system built into the Nova or you can email.