Essentially, if you do at least 3 stays, you get 1,000 bonus miles per stay, up to 10 stays.

There's another version of the promo floating around where you get the original 3,000 miles after 6 stays (instead of 3). That's the one I received, but instead I enrolled in this (better) promo. I hope everything will work out in the end.

Edit: found the original link [[redacted -- unnecessary after the merge]]
Edit 2: Just read that thread and I realized that I'm basically screwed...