OK considering how the game is a persistent(ish) world. Perhaps a encountered player list is necessary.
You could apply an icon to appear above players heads out of a selection of icons, to represent their relation to you in a personal way.
This could serve as a medium for keeping notes about players you encounter. Be they trader, raider, hero, friend, adventurer, explorer, ect... and if they are a trader for example maybe what resources they offer.
It...