[Adriaan]

What types of user behavior data might the search engines be using to reorder search results besides simple clickthrough rates, and how might those kinds of signals be used in determining sitelinks or quicklinks that Google, Yahoo, and Bing may show in search results?

[SEO]

  Well, for example where are you from (IP address), what you're searching (keywords), how long time you spend on the certain website...I think as a SEOer you should know these. 

[android45]

I completely agree with (SEO).