People on KB have been complaining that the Kindle Select promo system is not working well right now. People have books not going free for more than half a day after the supposed start time (this happened to me), books not going off free for a day or more, and promotions disappearing altogether. If our book is in Select, it might be a good idea not to run a promo just now, till Amazon gets this all straightened out. I'm personally a little annoyed that more than half of one of my five free days disappeared into the ether. Besides, all these problems can make us look like flaky idiots if we ask a blog to feature our "free" book, and they find that it's actually not free at all.
Just a FYI:-).