According to a February 2, 2010 article in The Washington Times, that answer can be summarized in one word: porn! As reported by The Washington Times, one regional supervisor at the SEC attempted to look up pornography on his/her work computer over 1,800 times in a 17-day span! And in all more than two dozen SEC employees have attempted to access pornographic websites over the past two years. Although the names of the employees were not disclosed, one employee admitted accessing pornographic sites on numerous occasions over a one year span, but he tried not to let it affect his work! Sure.
It appears most of the employees have undergone some sort of disciplinary action, but short of termination, although some resigned short of an investigation.
The Washington Times article can be viewed in full here: http://m.washingtontimes.com/news/2010/feb/02/sec-workers-investigated-for-viewing-porn-at-work/?feat=home_headlines

