Use This Egg By.....

When dieting one of the things you learn is that proteins will keep you filling full so you should include a protein with every meal or snack.  Eggs are a good source of protein and in my opinion worth the 2 pts plus each (can't stand the taste of egg beaters - blah...); anyway this morning I get up and decided to have 2 scrambled eggs.  I had just bought eggs within the past week, so imagine my surprise when I opened the carton and saw this:

Yep, each egg was stamped with a use by date!  Is this something new?  Something only certain stores do?  This is the first I've ever seen it.