It absolutely did work in the case of 9/11. It forced Muslims to take sides, that's why Muslims follow their religion in a stricter fashion today,especially in the west, in time of war there can be no moderation and Muslims feel they are at war against non Muslims,whether they admit it or not.

And it had an effect of humiliating USA in front of the whole world, but one has to be a non US citizen to understand that fact. Suddenly USA stopped being that all powerful nation, suddenly US looked like it could be beaten. It sent a strong message to all the people and groups that despise USA around the world.

Bin Laden absolutely won this battle, he lost however his battle against the Saudis as he thought 9/11 would provoke a revolution in his own country. That never happened.