AFK (away from keyboard) is “in-world” speak for the state of your SecondLife avatar when you’re not operating him/her. I’ve also heard this state referred to as “asleep” or ”latent.”
I sought out this terminology a week or so ago when I noticed the opposite phenomenon. I was with a group of social media cronies at a conference or happy hour or breakfast and realized that we were the opposite of AFK–ATK: attached to keyboard.
There was a lull in conversation while we all hung our heads–like sleeping avatars–to tweet, text or type. We had checked out of the real world and were only existing in the virtual/online world. In this group, this ATK behavior was completely socially acceptable. In the technology, social media and web communities, there is an unspoken understanding when you step out of the in-person conversation and go ATK. It’s almost like we live in a hybrid online-offline world.
However, in the non-tech, regular offline world, going ATK is NOT acceptable. To your family, colleagues and friends, you may appear as exciting and conversation an avatar that’s AFK.

I liked the simile about hanging your heads like sleeping avatars! Thanks for the laugh.