You don't actually earn airline miles with this card ... you earn BonusMail points, which can be redeemed for frequent flier miles.
Currently BonusMail only offers Alaska Airlines Frequent Flier miles. They like to tout that you can use these miles on several different airlines, but I still wish they offered Delta (or United or American or something ...). They used to have more choices, including United, so I don't know if Alaska Airlines is their choice for now, or if they will maybe change airlines again in the future. You can find out more about BonusMail at:
http://www.bonusmail.com
And if you should happen to decide to sign-up, tell them
[email protected] referred you ...