This article surveys the use of eye tracking in investigations of online search. Three eye tracking experiments that we undertook are discussed and compared to additional work in this area, revealing recurring behaviors and trends. The first two studies are described in greater detail in Granka, Joachims, & Gay (2004), Lorigo et al. (2006), and Pan et al. (2007), and the third study is described for the first time in this article. These studies reveal how users view the ranked results on a search engine results page (SERP), the relationship between the search result abstracts viewed and those clicked on, and whether gender, search task, or search engine influence these behaviors. In addition, we discuss a key challenge that arose in all three studies that applies to the use of eye tracking in studying online behaviors which is due to the limited support for analyzing scanpaths, or sequences of eye fixations. To meet this challenge, we present a preliminary approach that involves a graphical visualization to compare a path with a group of paths. We conclude by summarizing our findings and discussing future work in further understanding online search behavior with the help of eye tracking.