I don't watch Dr. Who and never got into it, and I consider myself a card-carrying geek. Good luck to anyone that wants to disenfranchise me. 
> geek

> Slang.
>
>noun
>
>1.
>a digital-technology expert or enthusiast (a term of pride as self-reference, but often used disparagingly by others).
>
>2.
>a person who has excessive enthusiasm for and some expertise about a specialized subject or activity:
>a foreign-film geek.
>
>3.
>a peculiar person, especially one who is perceived to be overly intellectual, unfashionable, or socially awkward.
>
>4.
>a carnival performer who performs sensationally morbid or disgusting acts, as biting off the head of a live chicken.

And under the given definitions, I'm pretty sure any active member of this community qualifies as a geek.