Is it true that Pampers gives away coupons for free diapers?

I was just watching "Extreme Couponing" on TLC and one of the "couponers" explained that she sent a letter to the Pampers company. She said they sent back some coupons for free diapers. Do they actually do this? If not, do they send coupons for money off or other items? All answers are appreciated. Thanks!