This article explores information sharing in the context of amateur genealogists researching their Irish ancestry. Information sharing is an important feature of this hobby, with individuals networking with others to supplement information they have found when searching sources. Because of the nature of the hobby, reciprocal sharing behavior may be significant in this process. This study adopted a multi-case, exploratory approach to learning about amateur genealogists' sharing behavior associated with their information seeking. Twenty-four amateur genealogists from around the world participated in semi-structured telephone interviews about their hunt for their Irish ancestors. Data were transcribed and analyzed to identify patterns and conditions of information sharing between participants as they researched their genealogy. Participants in this study were avid information seekers, who prized information sharing as a means of advancing their research. The Internet played a central role in information sharing. Particular social norms surrounded the sharing of information that shaped interactions, including expectations of reciprocal information sharing. The findings of this study suggest that information sharing is an important feature of hobby participation for amateur genealogists, supporting learning as well as achievement in locating one's ancestors. Reciprocal information behavior strengthened social relationships between genealogists and multiple information sharing events solidified the network positions of individuals as information champions.