The Population Reference Bureau (PRB), a nonprofit educational organization, aims "to increase the amount, accuracy, and usefulness of information about population trends and their implications." PRB maintains PopNet, an extensive directory of population information resources available on the Web. PopNet, "the Source of Global Population Information," contains numerous annotated listings of public and private population organizations around the world. Users may browse the PopNet directory by organization type, geographic region, or subject area. The directory is also searchable by keyword.