Can Facebook and Twitter change the world? Can all the nifty new social-networking sites promote democracy and a better understanding of American values around the world? The potential is certainly there -- as was seen in the invaluable Twitter updates during the post-election protests in Iran. The U.S. government is embracing Web 2.0 for an ambitious strategy of reaching previously untapped populations around the world -- call it Public Diplomacy 2.0. While the potential progress is undeniable, so is the potential danger.