Recently I’ve noticed some ignorance regarding what constitutes a tab, largely fueled by the announcement of the badly-named Tab Candy. Panorama is a much better name.
To clarify what a tab is, I looked for a random picture of a tab and added a circle around the tab.
If those tabs aren’t there in some kind of metaphorical pixel-form, there are no tabs. Or to put it another way, a tab-based user interface consists of multiple internal windows with a sort of task bar.