Gather Knowledge is the ability to subconsciously absorb and recognize information that is relevant or useful, even without actively searching for it. This skill represents a keen, passive awareness of details in the environment, allowing a character to pick up on rumors, symbols, patterns, and useful facts without deliberate effort.
Roll 1d100 against DR 100. The higher the roll, the more information. A roll of 100 might just let you know who the lord an area is and where a good inn is located, where a roll of 120 will let you feel if there is tension in the area, and a roll of 140 will let you know between whom.
After a party, a stroll through a city, a visit to a local tavern etc. ask the Game Master if you picked up anything. Harder if you are in an unfamiliar culture, do not spend a lot of time or if the knowledge wasn't communicated in an obvious way. You will not learn any deep secrets from this, but gain a good understanding of the area.
Gather Knowledge is used to acquire non-academic, street-level, or underground information. It applies to rumors, black market trends, criminal activity, faction movements, or recent events.