For the record, going to usairways.rewardsnetwork.com now brings a page with both US and AA logos. Doing my US login gives a pop-up saying they're combined and "Aadvantage miles" showing my US account number. Since in recent times I've only been active in the US program, I can't say what happens with people who've been active in both dining programs. I remember that with DL and NW my pre-merger logins for both accounts showed as separate DL accounts.