Recently I found myself (potentially) discussing the nature of a horizontal/top navigation bar (h-nav-bar) and a tab set without knowing it.
I know they're different, they feel different, at least to me. For example, I wouldn't share navigation items (like an vertical menu) across the items (One, Two, Three, Four) in the tabbed version (top), but I definitively do it in the h-nav-bar version (below).
Can anyone provide more insight on what's the cognitive difference between one and the other? What would user expect from one and the other?