A recent brouhaha about the outing of the notorious troll Violentacrez brought to prominence a term that's been around for a while, but that really got a workout in the last week: doxxing.
Doxxing, sometimes doxing, infinitive to dox, often used passively (to be doxxed), is to publicly identify someone who has an online persona that keeps them otherwise anonymous. In this case, the user "Violentacrez" was doxxed by a reporter for Gawker.com (link here, but is currently unavailable due, I believe, to wrangling between Reddit and Gawker). The incident has set off a huge debate on the Internet that involves overlapping discussions about privacy, free speech, ethical behavior, journalism, and other topics.
But we're not about ethics here, we're about words. Dox definitely has the sense of outing someone. The source is not entirely clear. It's possible that dox comes from docs, i.e., documents, as in, being documented.
If Urban Dictionary is to be believed (ahem), it also refers to intercourse, perhaps not of a variety preferred by one of the participants, with typical metaphoric overtones. (See also: screwed.)
There's this slightly odd sense (from 1998), in reference to a game that's for sale on eBay:
This could mean (I cannot verify) that the game is fully documented, as in, it comes with all the bits that accompanied the new product.
Another sense of doxxed appears in discussion about gaming (a world I know nothing about) and seems to be a specialized and unique shortening of "paradoxed," whatever that might mean:
A thread on the wordorigins.org site reviews these senses and Dave Wilton in that thread writes "I would suggest the first meaning above blended with the 'documents' sense to give the specific meaning of private information being revealed."
Since I have no actual, you know, facts, I'll echo Wilton's belief that doxxing in the "outing" sense seems like it could plausibly derive from documents. Perhaps someone can look into this a bit further. And then, haha, dox it.