It's fun. German-speakers are usually like, "Why would you pick 'Muckefuck' for your screen name?" Others are all over the map, from a crotchety old Australian who doesn't know the reference at all and dismissed it as juvenile potty humour to my favourite reaction ever (from an LJ meetup): "I have no context for that!"

I love Austrian German. Nuphy, my ex, told me about an old guide to Vienna which instructed English-speakers to thank people with the words "Donkey fieldmice". We actually heard this once from an elderly gentlewoman boarding the bus and were tickled beyond measure.