Understanding and modeling users of modern search engines

As search is being used by billions of people, modern search engines are becoming more and more complex. And complexity does not just come from the algorithms. Richer and richer content is being added to search engine result pages: news and sports results, definitions and translations, images and videos. Many such elements are added by search engines in their attempt to stand out from the competition by providing a superior user experience. However, the more complex search engines become, the harder it gets to understand users and their interactions with result pages, and to measure the quality of the user experience. In this thesis we address exactly this topic.