F1 is their other database which powers AdWords http://research.google.com/pubs/pub38125.html http://research.google.com/pubs/pub38125.html http://research.goog

F1 is their other database which powers AdWords http://research.google.com/pubs/pub38125.html http://research.google.com/pubs/pub38125.html http://research.google.com/pubs/pub41344.html http://research.google.com/pubs/pub41344.html