Dvd Proof of purchase?

[MAGIC]

i have a lot of dvds. ive always noticed the proof of purchase things above the bar code on teh case. they have dotted lines around them as if they should be cut out and use for something. Anyone know what? i guess im just hoping theres some kind of save them up for a free dvd thing or something. i dunno, just something i was wondering about when i bought V for vendetta tonight.

[GHoosdum]

I used to see offers for a free something-or-other-related-to-the-movie when sending in the proof of purchase, back in the day. Although, most of those offers were for DVDs in the cardboard cases, where the proofs of purchase were inside the spine of the case, easily detachable with perforations.