Earn Up to 8 Miles Per Dollar Spent on Groupon
I constantly preach about earning miles for "no-brainer" things like dining and online shopping. If you aren't already in on the game, you should start now. Most airlines have shopping portals that allow you earn miles on purchases from major retailers. In fact, the portal will take you directly to the retailer's website and when you arrive via a link for your preferred shopping mall, you automatically get miles.
For example, AA will give you 8 miles per dollar spent at Groupon if you arrive by way of their Eshopping mall link. Simply go to that site, enter your AAdvantage information, and then search for retailers. Once you click "Shop now" you'll be redirected to those sites and your AAdvantage number will be attached to your order - with most merchants, there's no need to enter it again at checkout. The system can automatically tell you were referred by AAvantage e-shopping and in a couple weeks the miles deposit automatically.
FYI: Delta also offers a 7 miles per dollar (and up to 10 miles for some) bonus through Skymiles Shopping. United offers 6 miles per dollar through MileagePlus shopping. USAirways offers 4 miles per dollar at the Dividend Miles Mall.
Of course, it always makes sense to document your purchases so you can chase the miles if needed, but mine always post automatically as long as I go through the airline affiliated shopping portals.