It is not that common to ask that question in Europe. People do, of course, but usually in a round-about way or in such a way that you can gracefully get out of answering. It is considered rude to ask it, because it is considered equivalent to asking someone how much money they make and because it might make someone feel bad (if they have a lousy or low-status job). Normally you would only ask that once you knew someone fairly well.
It's not something that comes up very often; most of the people I have conversations with are either coworkers or family members, so they already know my work status.
Funny, when I read your title, I was thinking you were going in a totally different direction and my first thought was, "I really don't hear that asked very often at all...."
I think when I hear that, the person has brought up "work" first.
I find it very common. Not upon a first meeting or upon introduction to someone, but later on when it's established that this might be an ongoing relationship (even if just a casual relationship like fellow band moms or the like).
I don't find the question to be any different in meaning or purpose/helpfulness than ages of kids, number of kids, church affiliation, etc.
"I don’t mind a banshee, that’s fine. 2 banshees? I HATE you. I actually wish bad things upon you." -- Day Daily #459 P1
While the subject has come up (most recently, last week) when I meet someone new, it's not always in the form of the question of "what do you do?".
The truth may be out there but lies are in your head. Terry Pratchett
what's NOT common is, where do you work, what kind of job do you have, what IS common is, what do you do which often