Those are for the MyFordTouch vehicles, the F-150 will get that unit in 2013. On those, the included SD card holds the map data for the Nav system. You can play music off an SD card if you want, but the Nav won't work while you do. The system also has 2 accessible USB ports for mass-storage devices or for a USB modem to get the built-in WiFi base station to actually do something. There are also RCA-in video jacks for the screen in the dash.
My wife's Edge has this system and none of this functionality is working because the system took a huge dump and no amount of fuse-pulling or battery disconnecting has revived it. So it is back to the dealer with it, most likely will need a new APIM module to revive it.