The Pebble wrist watch was supposed to start selling back in September 2012, which was four months ago, but it didn't, due to various setbacks.
One of them was the lack of FCC certification. The Federal Communications Commission has to test all devices capable of wireless connectivity, and since Pebble has Bluetooth, it qualifies.
Pebble will be colored in one of several hues when it finally ships.
Its role is to show the time, obviously, as well as receive and display e-mail notifications on the 144x168-pixel black and white e-paper
The watch will also notify of incoming phone calls, run apps for cycling music, running fitness apps, etc.
Several apps can be run at the same time, according to the user manual shown on the FCC website. See the full filing here