I don't go here

1. "I don't usually participate in this"

2. "I'm not part of this subculture/community"
3. (of a fanwork of some sort) "I'm not part of the fandom for this"

Generally paired with a "but" afterwards, to illustrate why the speaker is 'here' anyway.

(Usage note: I've only seen it used to describe the speaker. The first person form is the one most commonly used, but "doesn't go here" gets a very few hits on Twitter from people describing themselves in third person. There are some other third person results for the phrase, but it coincides with a Mean Girls quote, so I can't be sure whether this is the intended usage or not.)

"I don't go here, but the composition of your art is fucking amazing, holy shit."
"I don't go here, but I felt like I had to step in and clarify some things."
"I don't go here, but this is funny as hell."