FOAF (ontology)

FOAF ( Friend of a Friend) is a project for machine-readable modeling of social networks. The heart of the project is an RDF schema that defines classes and properties that can be used in an XML-based RDF document. It is in FOAF one of the first applications of Semantic Web technologies.


In a FOAF document information about a person ( inter alia name, age, gender, email address, address of the private and professional website, blog address, ICQ-/XMPP-/AIM-IDs, profession etc can published and the person known people are called. ). Once several people publish FOAF documents, such as the WWW, the FOAF documents can reference each other. A software can these FOAF documents evaluate, analyze, and visualize social relations, for example.

Another conceivable task would be personal data as mentioned above, Messenger, contacts, mail accounts, or the like to store at a central point ( FOAF file on your own server on the WWW ) and in processes such as logging into forums or various services specify the FOAF file without any data entered individually, and possibly also to change with changes yet. Corresponding add- ons or plug-ins are already available within some services.

Example of an RDF document with FOAF data

Several vendors are now issuing information about their members as FOAF file. This is to counteract a " silo - ization " of information in closed, proprietary networks. An incomplete list of providers that publish information in FOAF format:

  • Live Journal ( blog platform )
  • Tribe.Net
  • Videntity ( works more like OpenID )
  • Hitflip ( commercial)
  • Sendia ( commercial)
  • ( blog platform )
  • (open micro-blogging platform )


Under data protection point of view, each process, the machine-readable data and then makes it available to the world, an increased risk represents a standardization as FOAF makes the other by robots, automated data gathering feed. However, the should be countered with the FOAF SSL technology.