Right now, focusing on getting users. We do have some ads up, including:
1. adsense
2. affiliate marketing of airline and hotel credit cards (on your Delta "details" page, for example, you'll find a link to sign-up for the Delta amex card). A pretty relevant ad, given you're looking at the details of your delta miles and you're presented with an ad that allows you to earn 25,000 additional miles for signing up (or whatever the promo is).
Create a paid-enterprise model (think RescueTime) that tracks corporate rewards on credit cards. That way you could maximize reward usage and possibly save on overhead costs.
