I've been wondering about this myself. I have bad face recognition, and tend to remember people by hairstyles or glasses or facial hair. I can't really conjure up a good mental image of the faces of anyone I know, but I could give a fairly good description of people's haircuts, and different outfits they wear.
While I do look in the direction of someone's face some of the time in a conversation, I usually only notice their face when I am listening, and not always even then. When I am talking I tend to look around the room a lot too. It is almost impossible for me to talk (or think) while making direct eye contact, but I often talk while just looking in the general direction of their face, but I don't think I'm really picking up on facial cues then unless they are pretty blatant.
To me it seems like I can either talk, or listen, or read facial expressions, but not two at the same time. I recently realized that when I look at a person, it is usually just to indicate that I am listening, rather than to actually get any information from their face.
I don't know if this counts as eye contact either, I'd be interested to hear how it is for other people.