Civic Diplomacy is a part of diplomacy that everyone will graduate to after completing the Diplomacy Tutorial Quests and Civic Diplomacy Tutorial Quests when their diplomacy level is 4+. Civic Diplomacy allows you to create city wide buffs that will benefit everyone in (or just passing through) the city you are working in. Additionally, each successful Civic Diplomacy Parley will reward you with Diplomacy experience, Faction, Diplomatic Presence, and Information (which you can use to obtain that will boost your Diplomatic Presence).