Base Line Nerd Osmosis
The inescapable general baseline knowledge of fandoms even if you are not technically a part of the fandom, that you gained from being a nerd and talking to other nerds.
Person 1: How did you know so much about Doctor Who?
Person 2: Oh that, I got it from Base Line Nerd Osmosis with my sister.
Person 2: Oh that, I got it from Base Line Nerd Osmosis with my sister.