The threat advisories that were put out by the Department of Homeland Security were clearly not very effective. For this reason, the whole system of color-coded warnings has been scrapped.
What we now have is something called the National Terrorism Advisory System. This new system has only two levels instead of the five color-coded levels used previously. The reason for scrapping the old system was that it did not really give any useful information. This system was vague and did not really give people any sort of information that they could use to better protect themselves.
Of course, we have yet to see if the new system will work any better than the old or if there is simply no way to make a system that will be able to truly catch people's attention without seeming alarmist and out of touch with reality.