I've never placed "dork" in the same camp as "geek" and "nerd". For me "dork" denotes social fumbling, especially tied to romantic or sexual pursuits. The guy who sticks a "turbo" decal on his car to make himself seem more impressive is a dork. The bank clerk who got himself a gig writing elvish calligraphy for the Lord of the Rings films is not.

"Nerd" is closer to "dweeb" or "milquetoast" and suggests a refined intellect at the expense of physicality or, to some extent, real experience. The word "sophomoric" also comes to mind. Do people still use the term? I haven't heard it for some time.

"Geek" gets applied to anyone with a store of specialized knowledge.