On March 31 of this year Bungie will officially be out of the Halo business. So after that day, don't go checking bungie.net to check out your Halo stats because they won't be up to date. You are going to need to use Halo Waypoint for up to date stats. Along with the stats, 343 Studios will also be storing any user generated material and the Bunige Pro service. No word if they will change the name of that service though.
If you don't know how to get to Waypoint just go to halo.xbox.com