Back in 1984, the Computer Era was in full swing. It was a year when a slew of new words entered the Oxford English Dictionary, all devoted to computerese. Habitual users of the Internet became Netheads  and netizens; people were talking about WIMPs  as alternatives to command line input; some folks were discovering that a computer virus  could cause a fuckload of trouble ; yuppies  were discovering the Vodafone ; and people with an obsessive interest in computers became geeks.
In this sense of the word, the first written example is traced back to a Usenet group on February 20th, 1984, in a little couplet;
I was a lonely young computer geek,
With a program due most every week.
However, by the middle of the 90’s, it was being used in some cases as a synonym for nerd. Technology writer Rudy Rucker wrote;
Geek is the proud, insider term for nerd. If you are not a dedicated techie, don’t use this word.
Notice how he suggests that geek and nerd are synonymous but also asserts its status as a “techie” word. This continued into the early 21st century, as exemplified by an article in the UK’s Independent newspaper on June 4th, 2001;
We’re the nerds, the geeks, the dweebs: the men and women who can spend 20 hours straight contemplating 600 bytes of obscure, arcane, impenetrable computer code.
Now we have dweebs  added to the mix, but there is still the link to computer and software being made.
Yet although most people understand geek as an American slang word for technophiles, computer hobbyists, and software developers, it’s also a regional dialect word from the north of England, used to describe;
A person, a fellow, esp. one who is regarded as foolish, offensive, worthless, etc. (OED)
Although its first recorded use is in a dictionary of northern slang dated 1876, it made its way across the Atlantic and to the West Coast, where an edition of the San Francisco Examiner on 28th April, 1908 we find;
A geek who spends his spare time making Czar removers was slammed into the city cooler.
The meaning began to change during the first half of the 20th century such that by the 1950’s it had also come to be used to refer to “an overly diligent, unsociable student; any unsociable person obsessively devoted to a particular pursuit. (OED)” This definition is actually edging real close to that of a nerd.
So what then is a nerd, as opposed to a geek? Although there appears to be some interchangeability going on, the modern distinction is that a nerd is;
A person who pursues an unfashionable or highly technical interest with obsessive or exclusive dedication. (OED)
This is a more general definition than that of a geek, and indeed, it could be argues that a geek is a type of nerd, except that the “obsessive or exclusive dedication” is to computers and technology. However, it would be inaccurate to call someone who is, say, totally fascinated with etymology to the extent that they write about it every day as a geek, but they would mist assuredly be well suited to the title of nerd. 
The origin of nerd is still disputed and unlikely to be ever settled with any certainty. One popular notion is that it came from an animal in the book If I Ran The Zoo by Dr. Seuss – a small, unkempt, humanoid creature with a large head and a comically disapproving expression. More scatologically, another suggestion is that it is a euphemism for turd, but there is little supporting evidence, and it seems a very big stretch to somehow change the meaning of turd to nerd. Finally, one other etymythology is that it’s backward slang for drunk (“knurd”). I’d love this one to be true but again, it seems rather spurious and too good to be true; and in etymology, if an explanation seems “too good to be true,” it’s likely to be false!
The Dr. Seussian hypothesis at least has a better chance of being the origin. If I Ran The Zoo came out in 1950 and the first recorded use of nerd outside that book is noted by the OED as in the October 28th edition of Newsweek in 1951;
In Detroit, someone who once would be called a drip or a square is now, regrettably, a nerd.
So the conclusion to all this is that if you are knowledgeable and obsessed with computers and technology, you’re a geek, and if you’re knowledgeable and obsessed with trains, stamps, 19th century Romantic paintings, or etymology, you’re a nerd. Realistically, you’re probably somewhere along a continuum from geek to nerd but wherever you are on the spectrum, rest assured you’re not alone.
 From the net.women Usenet group, 26th November: “So, how about it, netheads?”
 From the net.followup Usenet group, April 10th: “For all you netizens who can’t appreciate a joke for its humor and must debate its theme.”
 Acronym for “Windows, Icons, Menus, Pointers.” These were first developed at Xerox PARC in 1973, and became the standard means of operating Apple and Microsoft computers.
 In Finch and Dougall’s Computer Security (1984) they wrote, “We define a computer ‘virus’ as a program that can ‘infect’ other programs by modifying them to include a possibly evolved copy of itself.”
 Modeled after truckload (1862) and shitload (1954), it appeared in an essay by Richard Meltzer where he wrote, ” I was struck by the fuckload of inner capacities the guy was perceptibly calling on.” Notice that even rock journalists are not immune from ending a sentence with a preposition.
 Another acronym, this time for “young, urban professional.” It appeared in a 1984 book by Marissa Piesman and Marilee Hartley called The Yuppie Handbook.
 Vodafone is a proprietary name for one of the first mobile phone networks that began springing up in the early 80’s. The word was used generically to describe any cellular phone.
 For the sake of completeness, and a gratuitous appeal to prurience, the word geek was also used as slang to mean, “A performer at a carnival or circus whose show consists of bizarre or grotesque acts, such as biting the head off a live animal.” Ozzy Osbourne was clearly not the first to bite the head of a live bat and was simply following an old American tradition for circus performers!
 Along with dweeb (1982), the word dork seems to be part of this family of words. Dork was first recorded in 1964 in an article in the American Journal of Speech as being slang for “penis,” a variation on dirk or dick and by 1972 it had become more generalized to refer to a stupid or contemptable person; in the same way you’d call someone a dick. Dweeb is thought to be derived from a possible blending of dwarf and feeb – the latter being slang for a “feeble-minded.”
 Using a sample size of one, I can attest to this being accurate based on my daughter regularly accusing me of being a nerd. She notes that I certainly have geeky tendencies, but fundamentally, she reckons I am a language nerd and the tech stuff is just a tool that lets me express and indulge my nerdiness. I won’t argue with her because she is, of course, absolutely right.