The information about the upcoming Hilton promotion that starts on January 7th and ends on March 31, 2013, was just leaked. You can earn double miles or double points during the promotional period.
“During the promotion, registered HHonors members can choose to earn double points or double miles between January 7th and March 31, 2013”
Hilton had a similar promotion in the 2nd quarter of 2012.
We should have the official press release of the 1st quarter promotion in couple of weeks. I have no doubt that the promotion will be for double points or miles.