For example, on WhatsApp, use the whole 25 character limit for profile name. Examples:
Bob Moved To Signal.org
Alice MovedTo Signal.org
CharlieMovedTo Signal.org
Say Signal.org, not Signal, because they won’t know it’s an app.
Use your about section too. Same on Discord, Steam, Instagram, etc.
Bob moved to -messenger-app-that-fails-to-deli ver-notifications
Bob moved to -messenger-app-that-never-syncs-properly
Bob moved to -messenger-app-nobody-uses
Bob has problems.
Bob had friends.
Bob has no friends.