Security Update
Serious question: what sensitive user data is there on Stack Overflow anyway?  Questions, answers and comments are all public, the content is Creative Commons licensed and even available in handy downloadable & queryable form: https://data.stackexchange.com/As far as I can see, the primary sensitive user data they have is e-mail addresses, but (unlike, say, Reddit) most StackExchange forums don't deal with personally embarrassing material and many of if not most StackExchange users post with handles easily associated to their real names.