Just a whine. Flew NRT-SIN-NRT in March, and just signed up for Mileage Plus today. I put the information into the retrocredit form only to be presented with the following message:
The flight segment requested was flown prior to your enrollment in Mileage Plus and is not eligible for credit.
I know it's my fault that I didn't sign up for Mileage Plus in March, but waaaah, that's 6,500 miles I can't claim!
Moral of the story: SIGN UP EARLY.
*goes away to sulk in a corner*