Really, I relate "nerdiness" with any kind of deep interest or passion. Although, not every person who is stereo-typically "nerdy" enough to browse /b/ necessarily devotes their time to something productive: be that learning an instrument, training your body, hacking, or whatever. There's a distinction to be made between "stereotypical nerd" (Poor social skills, good with computer, basement dweller) and what I consider "actual nerds" (those with a passion or deep interest in something that they then attribute an ungodly amount of time to).