Sometimes the spam from Citi is actually useful... like this email that I almost deleted: Enroll by 6/26/2012 to Earn:50% more American Airlines AAdvantage® miles*Enroll Now Click the "Enroll Now" button or call 1-877-564-5813. Your invitation number is: [redacted]The best part about your Citi® / AAdvantage® card? When you use it, your AAdvantage® miles can add up faster than ever.Click the "Enroll Now"** button to accept this offer and earn an additional 0.5 AAdvantage® mile for every $1 spent on eligible purchases until 8/31/12. That's 50% more AAdvantage® miles on what you buy.** Get packing!Maybe they heard somewhere that I just got the UA Club VISA from Chase that gives me 1.5 miles per dollar?