  Most social network analyses focus on online social networks. While these
networks encode important aspects of our lives they fail to capture many
real-world connections. Most of these connections are, in fact, public and
known to the members of the community. Mapping them is a task very suitable for
crowdsourcing: it is easily broken down in many simple and independent
subtasks. Due to the nature of social networks -- presence of highly connected
nodes and tightly knit groups -- if we allow users to map their immediate
connections and the connections between them, we will need few participants to
map most connections within a community. To this end, we built the Human Atlas,
a web-based tool for mapping social networks. To test it, we partially mapped
the social network of the MIT Media Lab. We ran a user study and invited
members of the community to use the tool. In 4.6 man-hours, 22 participants
mapped 984 connections within the lab, demonstrating the potential of the tool.
