Nothing new or different, other than that they must be used within the time window. I'm wondering if you meant the WDW Fast Pass system, in which case, you posted in a Disneyland forum
FP+ is at DisneyWorld. DL still uses the familiar paper return tickets, but they do enforce the return time now so you need to use the FPs during the specified return time.
If you want info on the FP+ system, there are many threads on the DW Theme Parks Attractions and Strategies board. A comprehensive start would be on this thread: http://www.disboards.com/showthread.php?t=3326057