I have just learned (and I'm steamed about it) that some Orbitz "Web Saver" deals are viewed by some airlines as "consolidator" fares and thus do not earn miles.

I bought an Orbitz AA RT SEA-STL-TPA for my wife and credited the flights to her BA account, but BA later ruled the flights "ineligible" for miles/points. This was an L class discount fare.

I don't know what other airlines besides BA make this distinction, but beware!