It appears that a satire based Wiki site, Encyclopedia Dramatica, accidentally uncovered that a Wikipedia administrator was an employee of the Department of Homeland Security and exposed it, after they learned he was suppressing possible evidence of the 9/11 attacks on Wikipedia articles. In response, that admin and others organized to get it quickly removed removed from Wikipedia. Full timeline is compiled here. Why is a USDHS employee suppressing information on Wikipedia?
Hat tip to MarkM for the link and story