The American Go Association has mentioned Order of the Stick twice:
https://www.usgo.org/news/2020/05/go...he-stick-1203/
https://www.usgo.org/news/2016/07/go...nd-woo-comics/
EDIT: The links are dead already? Here are wayback machine links:
https://web.archive.org/web/20200928...he-stick-1203/
https://web.archive.org/web/20191205...nd-woo-comics/