I have never owned a slide rule. I suspect that that simple fact excludes me from purebred nerd-dom. But why guess?
Over at Slackpropagation, A Web Journal about Machine Learning, Music, and other Mischief, they did a statistical sample of data using a developer portal at Twitter to look at over 26 million tweets. They found the following nerdy/geeky words and looked at whether they were also associated with “geek” or “nerd”.
On about 90% of these I agree. How “punk” got on the Nerd side I don’t know, ALL my music geek friends are into punk. Microsoft landing on the Geek side is also odd. But hey, this isn’t cancer research, it’s a frickin’ data whim.

Aah, but other than that it seems kinda bullseyeish, even the sad bits like “loneliness”, “autistic”, and “smartypants”. The full dose of info is fascinating. They took it pretty seriously. For example:
“Both are dedicated to their subjects, and sometimes socially awkward. The distinction is that geeks are fans of their subjects, and nerds are practitioners of them. A computer geek might read Wired and tap the Silicon Valley rumor-mill for leads on the next hot-new-thing, while a computer nerd might read CLRS and keep an eye out for clever new ways of applying Dijkstra’s algorithm. Note that, while not synonyms, they are not necessarily distinct either: many geeks are also nerds (and vice versa).”
There you go. Self categorize at your leisure.

A more thorough explanation of how they created this infographic can be found at their website. (http://slackprop.wordpress.com/2013/06/03/on-geek-versus-nerd/)