The term "geek" originally referred to the carnival performers whose act consisted of biting the heads off chickens and eating glass. Over time it came to be applied to anyone who got paid to do work considered odd or bizarre by mainstream society.

The term now enjoys a special status within the technical community, particularly among highly skilled computer programmers. To identify oneself as a "geek" indicates a recognition that most people still consider programming computers to be a bizarre act, along with a certain fierce satisfaction in being very good at their inglorious profession.

That most software geeks now easily earn twice as much as the average laborer just sweetens their defiant embrace of the term.

Note: Unlike the word "nerd," which is always pejorative, "geek" often carries a positive connotation when used by one of the group. The use of the term by outsiders is considered insulting.

-- urbandictionary.com