What is Orange Alert?

Travel Info
If there is an airport, for instance O'Hare International, that is at Orange Alert, what does it mean?

Travel Tips

It means a heightened security alert, at all U.S. airports which means all bags and packages are subject to thorough searches. Observing any suspicious behaviors.
Others

Orange is one of the color levels of the national terror alert system. Orange means "elevated level of alert". Not sure what we're supposed to do about it, though.
http://www.nationalterroralert.com/overv...
A "threat" alert to security.
U should listen to Bush's speech more because that's his favorite phrase.
It means it's time for the government to try and scare us again.
It means cram as many drugs and liquids into your carry on as possible.
Next the red alert, it is the second highest