Not sure if this has been discussed before, but ever since United switched to continental's website system, there seems to be problems where a single flight number is used for 2 flights with a stop in between. I've noticed the mileage is NOT counting the stopover anymore (counting mileage from A to C rather than A to B to C). Also, selecting distinguishing seats between the 2 flights has been impossible online. Last time, I got the same seat for both flights. On an upcoming trip, I could select different seats but the 2nd flight didn't let me select economy plus for some reason! And overall, none of my seat selections stuck. I called a rep and got seats assigned manually by web support (this was after a couple of reps told me it was impossible to assign seats for this situation). It sounds like they are having a lot of trouble with these kinds of routes in the continental system.