According to the article, anything related to your age or where you live is a pretty good indicator of what your voting preferences are. The article cites "90%

According to the article, anything related to your age or where you live is a pretty good indicator of what your voting preferences are. The article cites "90% accuracy" if your answers can be used to reasonably guess those facts. Additionally, if your profile is public (the default still, I believe) is made available when you comment, I'd guess there'd be follow-up scraping going on to collect more details that are then used in conjunction with whatever your response was.