Source : Free On-Line Dictionary of Computing

FOAF
     
        [{Usenet}] Friend Of A Friend.  The source of an unverified,
        possibly untrue story.  This term was not originated by
        hackers (it is used in Jan Brunvand's books on urban
        folklore), but is much better recognised on {Usenet} and
        elsewhere than in mainstream English.
     
        [{Jargon File}]