Genealogists sometimes specialize in a particular group

A small community, e.g., a single village or parish, such as in a one-place study; or a particular, often famous, person. Bloodlines of Salem is an example of a specialized family-history group. It welcomes members who can prove descent from a participant of the Salem Witch Trials or who simply choose to support the group.

Genealogists and family historians often join family history societies, where novices can learn from more experienced researchers. Such societies generally serve a specific geographical area. Their members may also index records to make them more accessible or engage in advocacy and other efforts to preserve public records and cemeteries. Some schools engage students in such projects as a means to reinforce lessons regarding immigration and history. Other benefits include family medical histories for families with serious medical conditions that are hereditary.