I suggest two different yet similar things:
- draw on items with some kind of permanent marker pen. The action would open some drawing area, just as the text area for writing notes. Then the drawing would be visible on the item (and player wearing/handling the item). I suggest such drawing shall not be easily erased from items.
Just think of having a bandit tally on your rifle, having fun with captives, or have actual visually unique items, to identify yourself, brag with, to communicate things or whatsoevery!
A similar, but possibly technically more challenging feature would be to have graffiti/wall drawings (with persistence) to communicate things. I often found myself thinking about how text notes could actually be used to communicate with other players, but it all stops because people will ont read them. Therefore:
- with spray paint in hands, add action to paint on walls or other environment objects. Such marks should probably belimited somehow, in lifetime or count, depending on the game server resources and performance choices.
My main reasons for those two are in the enhanced communicative game experience and gameplay possibilities.