There was a thread about "Hidden Tire Dangers" over at the Autopia forums that I thought might also be of interest here:
Here is the copy and paste of the first post:
"Hidden Tire Dangers, are your tires over 6 years old?
"Watch this vid it's important!"
From ABC News:
Here's another one from the Today show:
And, a picture:
"Just so no one else has to search for it, the four digit code is week/year "wwyy"
Prior to 2000 there was a 3 digit code."