Registration was easy. You just go to the Blizzard Authenticator
link on the Account management page. Enter in your authenticator's serial number and click "Attach!" It was easy to attach the authenticator to both of my accounts. As you may have noticed, I'm notorious for typos so I double and triple checked my serial number before finalizing.
You just enter your user name and password as normal, then the token entry screen pops up. Just push the button and enter the code on the LCD. Both accounts logged in with no apparent delay in processing. This little doohickey is meeting my expectations so far.
It looks like the token entry is only required for logging into the game. I was not prompted for an authentication code when I logged in to the forums.
Edit: I do wish that the LCD had a back light. However I usually have minimal light in the house and can use the authenticator. On the plus side, it means the batteries should last longer.
Silly question, you can associate two accounts with one, can you be logged on to both accounts at the same time still?
Yes, I have logged into both accounts at the same time.
Can anyone explain how these work and how they are unique to everyone?
The reason that you have to enter your serial number is because each authenticator is coded differently. Just how my boyfriend and I both drive fords, but my keys won't start his truck (super hot 2000 Lightning) and his keys won't start my car (Yes, I drive a 2006 Mustang GT and I'm incredibly proud of it).
What happens if you loose or damage your Authenticator? Is there any way to get your account back?
You'll call customer service and they can deactivate the authenticator from your account. Same thing if it runs out of batteries. You have to make the call, you can't do it from your computer.
Is it built for long term use?
Yes, blizzard expects it to last for several years on the battery included in the package. That's one of the upsides of no backlight. Think of it like the key fob for your car. Yeah, the batteries will run out, in a decade or so. You'll just call and replace the authenticator if that happens.
So do you have to enter this extra code every time you log in?
Yes, and the code is different each time, so even you shouldn't be able to crack your own code.
Can I press the button and quickly give him the numbers to enter from a different location, or will it just not work?
While you shouldn't be sharing accounts, the answer to your question is yes. The authenticator is time specific but not location specific.
What do you do when the batteries run out? Can they be changed?
The batteries can not be changed, but you can buy another authenticator for another $6.50 if/when the batteries die.