Proactive steps to prevent DDOS?

Ok, Yahoo, Ebay, Amazon and Microsoft have all made essentially the same statement after being hit by a DDOS: "taken steps to improve protection of their networks from this type of attack." My question is What are these steps, and why can't people take them before they experience a DDOS? Is there some magic command I can put into my router to help protect my network from a DDOS, or is this just PR fluff to make it look like the corporation is doing something. But in reality there is nothing you can do, but wait for the attacker to get bored and stop on their own.