AT&T went a step further to inconvenience wireless charging enthusiasts, as its version of the phone supports the PMA standard, rather than the more popular Qi. Of course, this is a natural choice on the carrier's side, since AT&T is a member of the Power Matters Alliance and it would make little sense to see it turn its back on its colleagues and push a hot flagship bearing Qi-support. What this means for AT&T subscribers is that their choice of optional accessories is severely limited, since third-party accessory manufacturers prefer to go the way of the Qi. The choice of mats is down to Duracell-made ones, since the battery manufacturer is another member of the PMA. The choice of a back plate is currently only one – the official Quick Circle case.
But hey – there's a bright side. Starbucks is also a member of the Alliance and is equipping its coffee shops with PMA-standard mats, so if you like to frequent one of the chain's cafeterias – they've got your wireless charging needs covered!
source: Droid Life via Android Community