From the language survey, there were quite a few questions dealing with word choice (e.g., coke, soda, pop). There are also algorithms that can predict, with varying levels of accuracy, the writer's gender [1]. Combine these with browser font identification [2], geolocation [3], and other comparable data, and lying or omitting data isn't going to provide much in the way of anonymizing you or your data.
[1] http://www.hackerfactor.com/GenderGuesser.php