The other night a friend of mine tipped me off to a second, older, meaning for the word otaku in Japanese. I’ve only heard it applied to geeks. オタク go to Akihabara    and live for video games, anime, and figurines… or so the legend goes.
Apparently it can also mean “your house.” My guess is that it is a little formal and polite, but I’ll have to run that by my Japanese teacher to be sure.
お宅 – your house
オタク – geek