I went to Nakano broadway (It's the Mecca of Japanese subculture) today for the first time in almost 10years.
I was happy because there are no change and I realized again that the place is awesome.
I find the difference between foreign "Otaku" and Japanese that.
The original term has much more meanings not only about anime, "Otaku" contains someone enthusiastic to one thing.
So, maybe the word "Geek" is similar to original "Otaku"? I don know well.