An aggregated search interface is designed to integrate search results from different sources (web, image, video, blog, etc) into a single result page. This paper presents two user studies investigating factors affecting users click-through behavior on aggregated search interfaces. We tested two aggregated search interfaces: one where results from the different sources are blended into a single list (called blended), and another, where results from each source are presented in a separate panel (called non-blended). A total of 1,296 search sessions performed by 48 participants were analysed in our study. Our results suggest that 1) the position of search results is significant only in the blended and not in the nonblended design; 2) participants’ click-through behavior on videos is different from other sources; and finally 3) capturing a task’s orientation towards particular sources is an important factor for further investigation and research. Categories and Subject Descript...