Maybe this happens a lot, but I just noticed for my son's account he got a targeted offer, after having just flown on Dec. 30: Exclusive offer: Earn 2,500 bonus award miles. Make your next trip even more rewarding. Earn 2,500 bonus award miles on your next flight when you register, book your flight on united.com and fly by January 31, 2012 When I clicked through, it clarified that it would be: 2,500 bonus award miles. Any roundtrip flight. Link allowed all of the rest of the family members to register, too, but not sure if we'd actually get any miles.