Beneath the teaser are the various accolades/awards AT&T has received from the press regarding its network. Different AT&T employees tweeted it was a "big announcement."
We still aren't sure what this event will be about, but we figure the company is getting ready to delivery some news regarding LTE-Advance, VoLTE, or other network news. Especially since the company has been rumored to launch VoLTE sometime in 2013.
We'll keep you updated with any other information we hear.