its targeted, i got this too:
As an elite member of Starwood Preferred GuestŪ, you can earn 5,000 bonus StarpointsŪ (up to a total of 15,000) after every five stays between March 1 and May 31, 2007. Simply register by April 15, 2007.
others have reported 3 6 9K (pretty much stary nights redux).
Registration link:
https://www.spgpromos.com/quarterly/...=VTY_SPG_promo