I just received an e-mail from American Express related to my Hilton HHonors card. At the bottom of the e-mail is a blurb with a link:
"Shop Online. Earn Rewards.
See how using your Card as your online form of payment earns you more rewards.
Learn More"
The link does not properly direct to a page with more information. However, this supports my theory (derived from having received extra points from a few different online merchants in the past couple of months) that AMEX is going to provide bonus points for online purchases generally, perhaps as an alternative to the bonus points mall.