[Iceberg]

Definitions of geek on the Web:
A geek is a person who is fascinated, perhaps obsessively, by technology and imagination. Geek may not always have the same meaning as the term nerd.

Definitions of nerd on the Web:
Traditionally, the designation nerd (occasionally in the form nurd) applies to an intellectually gifted (probably > 120 or so IQ) but lonely and socially awkward person, one fascinated by knowledge, especially science and mathematics, and less interested in physical and social activities. Visual impairment (hence the glasses) and some form of High-Functioning Autism are also common characteristics, and the social impairment can often be explained by the latter.

Definitions of dork on the Web:
jerk: a dull stupid fatuous person.

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So basically, in terms of importance classification a nerd comes first, followed by a geek and the dork is last.