Argument: Anonymity on Wikipedia is an important privacy protection
Burt Helm. "Newsmaker Q&A". Newsweek. December 14th, 2005 - [Burt Helm:] "Seigenthaler's main criticism of Wikipedia is that contributors are allowed to edit and add to articles anonymously. Why do you feel it's important to allow contributors and site administrators to remain anonymous? [Jimmy Whales:] There are two reasons I would put forward. First, on the Internet, it's impossible to actually confirm people's identity in the first place, short of getting credit-card information. On any site it's very easy to come up with a fake identity, regardless.
Second, there are definitely people working in Wikipedia who may have privacy reasons for not wanting their name on the site. For example, there are people working on Wikipedia from China, where the site is currently blocked. We have a contributor in Iran who has twice been told his name has been turned into the police for his work in Wikipedia. He's brave. His real name is known, actually. But there are lots of reasons for privacy online that aren't nefarious."
The New Yorker article included an interview with a Wikipedia administrator known by the pseudonym Essjay - "I am a tenured professor of theology at a private university in the eastern United States; I teach both undergraduate and graduate theology. I have been asked repeatedly to reveal the name of the institution, however, I decline to do so; I am unsure of the consequences of such an action, and believe it to be in my best interests to remain anonymous."