FOAF

A FOAF is a "friend of a friend." Most often, people use this acronym when referring to someone they know tangentially, through a friend. For example, your BFF Cindy might say "a FOAF said she could score us tickets to the concert." This means a friend of Cindy's friend can hook you both up with concert tickets.

In some cases, people may use FOAF to refer to the Friend of a Friend project, which is an online collection of machine-readable profiles that describe connections between people. Ontologists use the FOAF collection to study social networks (and the activities that take place within those networks).