Shortcuts: +tag: add tag, -tag: lose tag, @name: add friend, #name: lose friend
Tags dictate what messages you see. When anyone, anywhere types a message that includes your tag, you can hear that person.
Adding a friend to your friend list will allow you to always see messages from that person.
Messages you see constantly change depending on the conversation, so if you're talking with someone, add them as a friend to ensure they don't disappear.