I got the same promotion in my email today. I'm surprised to get the "we haven't seen you around in awhile!", since I've flown 3 paid roundtrips in the last month, the most recent one on April 12. The email started with "Your Rapid Rewards A-List Member update", so I wonder if this is targeted to certain or all A-Listers?

Anyway, I have plain old text email so there was no registration link. When I first got the email I logged into my account and looked under Promotions and didn't see anything new. Waited an hour or two, logged in again and checked Promotions and the new promotion ("EXCLUSIVE OFFER - BONUS CREDIT 4/23-6/12/09") was available for registration.