What’s the difference between a geek and a nerd?

Thanks to Dictionary.com for the following definitions.
Geek,
a peculiar or otherwise dislikable person, esp. one who is perceived to be overly intellectual.
a computer expert or enthusiast (a term of pride as self-reference, but often considered offensive when used by outsiders.)
a carnival performer who performs sensationally morbid or disgusting acts, as biting off the head of a live chicken.

Nerd
a stupid, irritating, ineffectual, or unattractive person.
an intelligent but single-minded person obsessed with a nonsocial hobby or pursuit: a computer nerd.

Nurd
a foolish, inept, or unattractive person.
a person who is single-minded or accomplished in scientific or technical pursuits but is felt to be socially inept.

Seems to me there is not a lot of difference but they both suggest someone who is a social outsider. I raise this today because recently a couple of my friends have referred to themselves as geeks or nerds and I would not have put them in that category. Last night I was asked to chair one of our local neighbourhood meetings. Dog fouling was brought up because I’m not alone when it comes to this issue. When I mentioned it was Poop Scoop week at the end of June I was looked at with a great deal of incredulity. I then said “I’m a bit of a geek when it comes to info like that. Afterwards though I thought, no I’m not! this is just good community info which all our councillors should be helping with. When I thought about my other mates who had claimed to be geeks I have to disagree. We use the term far too easily. They’re not geeks just dedicated to their hobbies.

Ps “Sean the romantic geek” how about sending me the poem “You shaped hole in my heart”? I’d like to publish on this site.