United sent me a $50 travel coupon by email, because I went and fetched our luggage from MSN rather than waiting for them to bring it to us.
I'm pleased, but I'm also unsure how to keep track of it; chances are good that next time I fly, I won't remember I have it.
My usual tracking system with paper flight coupons consists of burying them in the pile of papers on my desk, vaguely remembering that they're there, and digging them up when I need them (sometimes even before they expire); for example, I have a free-flight coupon from Northwest (?) (which I really should've used to go to WisCon, if I had remembered I had it) that was buried in the papers on my desk until I (probably) moved it into the bigger piles of papers on my floor, where I'll never see it again.
So that's a fine tracking system for paper, but how will I remember that I have the email one?
I got several email coupons for various Treo-related things a year ago when I bought my Treo, but I suspect they've all expired by now; I keep forgetting I have them. And my uncle got me an Amazon gift certificate last year that I also keep forgetting I have. Must come up with some better approach to this. Perhaps journaling about it will make me more likely to remember.