I'm fairly a new player to Kingdoms of Travian, I do have a general understanding of many things but farm list isn't one them. The idea of having a kingdom is great, but sometimes attacking people around you can be hassle to choose from and could be a "race" of who gets there first. Yah sure you can communicate with your alliance/friendlies around you via Instant Message in game, but I got the idea of adding more to the feature of "Mark a Field".
First off, I love the idea of marking a field, it's amazing and its very useful but it can also be developed quiet further. Adding options such as a "Farm List" box could be interesting and you can select who can see them like that members from your alliance, kingdom or even secret society could help you out or just not disturb you because you already plan to attack X person.
Second thing would be adding the ability to show you mark fields for secret society. They are supposed to be secret but they have to have a purpose other than being able to chat with each other and compare statistics.
I've photoshopped a quick idea on how it would look: http://i.imgur.com/VF5aGx0.png ; adding the "secret societies" option which would have to change the features to be multi-toggle-able (meaning you can either toggle alliance/secret society, or me/secret society)
Also, now I understand you can join multiple societies, so maybe having a "drop down" box where you can select which society you want to show.
Now obviously my "design" is very poor, but I can design a better one if you guys want a better idea on how it would look.
tl;dr Add more features to "Mark a Field", Allow us to mark farming fields and be able to show alliance/kingdom and integrate Secret Societies to have their own designated "box" where you can mark fields for each other to discuss about.