I would more describe it the following way. Vertical tabs solve a core issue in horizontal tabs. Tabs are inherently 2D: the number of tabs vs the length of th

I would more describe it the following way. Vertical tabs solve a core issue in horizontal tabs. Tabs are inherently 2D: the number of tabs vs the length of their titles. Horizontal tabs can scale only to one dimension. You can choose to either see many of your tabs at once, but not be able to read any of the titles, or be able to read the titles but have to scroll absurd distances just to view what tabs are open. Vertical tabs give you a 2-dimensional view of your tabs. You can see many of your tabs and be able to read as much of the titles you want by scaling the horizontal size of the area independently. I think it's brilliant. I also don't see how browsers could "fix" horizontal tabs without resorting to taking away valuable vertical space from the content that is the primary purpose of browsers.