Originally Posted by nako
My understanding is the opposite on this - that is, the miles towards upgrades counter is based on Q-miles, not actual miles flown.
I can confirm from my own flying and record-keeping that the 500-mile minimum holds at least on AA flights - I haven't done any code-shares so I don't know if it differs there. But AA flights get (at least) 500 miles towards upgrades.
JDiver's post reminded me that I should also plug
McFlyPHL's spreadsheet, which is the facility for my aforementioned "record-keeping" and is available
here