Continuing more suggestions, i have another that would be for both thieves and traders and include all guilds in its function, graffiti

As a illegal act, spraying graffiti would imprint a temporary message on a building or door or permanent object (already currently existing buildings and doors could be used). If caught in the act (during painting of the graffiti), a guard would arrest said person for defacing public/private property, (or whatever this would be called)

Other players could accuse you of graffiti to the guard if they saw you paint, and Any player could, with a bucket of water and a towel/soap or whatever, clean the graffiti off the wall. This could teach a negligible amount of mech lore

Otherwise, after a period of time eg a day/week/month or something, the graffiti would automatically come off as some npc slowly walks around and cleans it.


[The Crossing, Town Green North]
A small path of bent grass leads to a narrow stretch of cobblestones between the grass and the privet hedge that stands before Milgrym the Weaponsmith's. The town's main source of serviceable arms, Milgrym does a good trade and has a solid reputation. The stream of customers, though steady, seems careful not to disturb the usual tranquility of the facing greensward. You also see a grizzled old war veteran, the town green pond and a public listings board. Some graffiti has been painted on the public listings board that reads, "spookey was here!".
Obvious paths: north, east, southeast, south, southwest, west.


[The Crossing, Town Green North]
A small path of bent grass leads to a narrow stretch of cobblestones between the grass and the privet hedge that stands before Milgrym the Weaponsmith's. The town's main source of serviceable arms, Milgrym does a good trade and has a solid reputation. The stream of customers, though steady, seems careful not to disturb the usual tranquility of the facing greensward. You also see a grizzled old war veteran, the town green pond and a public listings board. Some graffiti has been painted on the Weaponsmith's that reads, "if you want better stuff, stop by my shop in the plaza".
Obvious paths: north, east, southeast, south, southwest, west.