I shouldn't get it :-) I linked that question from the main CodeGolf site. I am 100% certain that I linked this question only within SE. Why would I link this very particular question from the outside webs?
Is this a bug or a feature?
I think it shouldn't be like that - you should be awarded for your effort outside to let people know about SE. Linking within SE is valuable, but I feel these badges are intended for propagating SE and it should be consistent in that.
EDIT: thanks to the discuters. Got an idea for possible solution.