Can some one please explain the difference between posting content directly on a persons Facebook wall whom in on your friend list and tag a person not on your friend list in the comment section on a page posted photo (tagging a person by name in a photo comment)?
When you post something on friends' wall, friend will get a notification and it will be visible to friend's audience settings and it will also visible to your audience that you have posted on your friend's timeline.
And when you tag anyone in a photo comment who is not your friend, the person will get a notification that you have tagged him/her. You friend's will see that you have commented on a photo in their news feed. But your non friend's friend will not see in news feed that he/she has tagged in a comment. They can see only by going to comment.