If you don’t know that Firefox Panorama is, which is included in the Firefox 4 Beta, check out the video on this page:
I must say that I really don’t get the point of this feature. Why do we need to have this panorama thing to organize tabs? Why not just open a second window, which is much easier to switch to instead of messing around with this panorama stuff? The only feature that would be needed then would be a way to close Firefox and all windows at once and save all of their tabs.
My point is – Firefox Panorama is pointless.