You can earn 1,000 bonus miles with either United, American, Delta, or US Airways for signing up with Thanks Again.
1. Go here and sign up for a Thanks Again account.
2. Next you need to sign up for the 1000 point promo which requires a Visa card number and a cell phone number.
3. Login to Thanks Again account – Click My Account link – Click the banner on right side of screen which says “Want to get rewards on-the-go? – Follow the registration process
4. The miles should post to your account w/in 4-6 weeks
There have been several reports of people being able to earn the miles for all 4 programs by signing up for each one individually with a different Visa card and using Pinger (text free) in the signup process. But keep in mind the terms & conditions state that there is a limit of 1 mileage bonus per household.