yap..they are doing surveys randomly. I was being interviewed the same and proved to be legitimate about six months ago. They are asking some sort of info related to your work and living condition. Better is to take a phone number from them and call, try to confirm about the guys identity. Mostly they are looking for families..for what they are going to use it, is quite hard to dig from the guy because his english is quite difficult to understand. Try to get someone who speaks arabic so he can explain exactly what it is all about. You can refuse the interview if you want, he won't force you.