I'll admit to extension, but not over-extension.
I think it's reasonable to extend the term "doxxing" to cover not only the initial step of internet haters tracking down the person's identity, but also -
- tracking down of other information, (or "information") about the subject
- using of that information to harass and humiliate the subject
Internet "sleuths" going on a hunt for details of Reade's personal history, in order to build a dossier for the purpose of damaging her reputation and challenging her credibility, totally counts as doxxing in my book.
Appealing to urbandictionary.com as an authority that what's being done isn't "technically" doxxing, doesn't make it any less repugnant, or any less in the same spirit.