Earlier quoted context omitted.
This suggests an interesting way of looking at the problem, namely "How do we make the site less interesting for non-hackers?"
Perhaps require solving a hacker-related "captcha" for submitting stories or posting until your karma has passed a certain threshold. For example, fix a line of code or enter the order of complexity of an algorithm.
Sweet! Then we'd get major practice in for our Google interview as well. Don't forget puzzles involving sparrows, rowboats, candles, and ropes for those of us who might be elsewhere-bound.