Being from the Tidewater area of Virginia, which is where PETA is located (ACK!), the four letters (to us) mean:
People Embarrasing the Tidewater Area
Of course there is also a few other favorites:
Please Eat The Animals
People Eating Tasty Animals
Let's face it, I cannot take them seriously. After all, they have Pamela Anderson as a spokeswoman. In this case, they need to get a grip on reality.