What does Proof Of Purchase tabs mean on the back of DVDs and other certain products?

Question

I heard you send it to some place and get some stuff, what are they for and what do you get

Answer 1

pop-is proof of purchase and it is required to know the date of purchase of the product and even bar-code sticker their will be manufactured date and year to conform weather its under warranty r not

Answer 2

It means if the producer of that product ever wants to give something away to people who buy it, then that is what you will send in as proof.

Answer 3

if they are promoting something for whatever you bought then you send in the POP otherwise its the barcode that if scanned proves you bought the item and that you didnt steal it.