Starwood is teasing on their Twitter and Facebook feeds about the new promotion that will be open for registration on May 1st.
The only hints that the Starwood has given out so far are that the promotions is:
ALL ABOUT YOU
CHOOSE WHEN, WHAT AND HOW YOU WANT TO EARN
So, the basic assumption is that this is a choice based promotion. Starwood has run something similar in the past where you can choose your preferred reward out of few choices. I cannot remember Starwood ever having a promotion where I could decide when I would earn.
I am probably not the only one who is eagerly waiting to learn more about this promotion. We should know in the next week or so.
In the past two summers Starwood has been running a promotion for a free hotel night after certain number of stays (3). The number of complimentary nights that one could earn has been unlimited.
In 2010 those nights were valid for weekend stays (Friday/Saturday/Sunday) at most Starwood hotels. In 2011 the promotion was for free nights at properties classified as resorts. These nights were valid 7 days a week.