Pledged in the case of becoming a baron means you have joined the military of the Duke and agreed to turn your town into a military outpost for the Duke. One could still pledge to work with a Count and/or a Duke economically and remain a Mayor.
Pledged in the case of becoming a baron means you have joined the military of the Duke and agreed to turn your town into a military outpost for the Duke. One could still pledge to work with a Count and/or a Duke economically and remain a Mayor.
The real difference (from my perspective) is that barons have a contract with a duke that specifies that they are a baron rather than a mayor.
Edit: The terms of these contracts likely will vary so expectations will probably depend on your own agreements with the duke/duchess.
They are basically the same pledge just with different focuses. The Mayor, of course, will be more focused on building the community through economy or trading. Their focus will be on building and expanding the land of the community, supporting crafters and guilds, providing support for the explorers as well as the travelers, as well as providing a safe place to buy and sell items both inside and outside the walls.
On the other hand, the Baron (A Mayor Pledge Tier) will be focused on the military and security of the lands. Usually the Baron will have a contract with the Duke to help fund the Stronghold or Outpost in return you will pledge to support and protect the Duke's land and well as the land of the King. A Baron will need help with supplies such as armor, mounts, weapons, and food to house and train the military on a constant basis so that is where the contract with the Duke comes in. It may be necessary to be located in a area specified by the Duke to compliment his overall security plan for the land instead of letting the Baron choose on their own, but that will be part of the negotiation between the Baron and the Duke.