What if all the islands had a tree or rock that pirates could sign their name to. Smaller islands might just be a scrawl in the sand. Taverns might be carvings in the tables or bar. By doing so, the players gamertag appears on the surface for the current session, then slowly fades after they've signed off. It could say something like, "Captain Arcanic recently roamed this isle!" Or Captain Arcanic drank at this tavern!"
Besides offering some session based notoriety, I'm not even sure what use it would be. The idea just sounded interesting and fun in my head. Maybe to mark legs of a race?
If I saw a pirate's name scrawled on the wall of the tavern, then crossed swords with them the next day at the skull fort, it would be fun to say, "Hey! I heard you drank at the tavern last night? Give my regards to the ferryman when you see him!"
Any other ideas for uses?