On the other AA 100,000 thread the OP was nice enough to send me the full email from AA becuase I was wondering why in 8 years I have not received any. It didn't seem to make sense.

In the email the following text was included:

"Unsubscribe Information
If you no longer wish to receive these marketing messages from American Airlines, please visit: http://info.aa.com/Key=43084.CQ.M.C6XPLR or reply to us and type "Unsubscribe" in the subject line."

Based on this I logged onto my AA account, went to profile, then Contact Inforamtion tab. At the bottom below my email address entry were some selections about subscriptions. One was AAdvantage promotions. Mine was marked as "Unsubscribe". I just changed it to subscribe in case this is it.

This also can be changed from the tab Email Subscriptions. Both are linked as changing one changes the other.

I'm not sure if this is it but it certainly sounds like it could be.

I just noticed the same thing on my Hilton Account and am opening it up!