"Ball Knowledge" is a growing phrase used by fans of sports to indicate that someone has a deep understanding of what they are talking about. An example would be saying something like the star is good but this guy whose on a worse team nobody pays attention to is better. What is a key indicator of "Ball Knowledge" in your area of interest? It could be a musician or writer that if they know you know they know what they are talking about or a clothing brand that if they wear, you know they have style.