Collaborative information seeking (CIS) involves people seeking information collaboratively for a common goal, where the information seeking is intentional, the collaboration explicitly defined, and the goal is mutually beneficial. CIS focuses on how groups of people understand search tasks, formulate queries, determine results relevance, share results, make sense of the information, and use information collaboratively. People collaborating on information-seeking tasks work in distinct ways, they should be studied and supported separately. Predominant literature focuses on and considers information retrieval as an individual activity. While there has been a growing interest in understanding and supporting CIS practices, we still lack clear understanding of people’s CIS behavior. CIS activities are supported by collaborative search tools.Thus, investigating and gaining better understanding of these activities is important for designing and developing effective collaborative web search tools.