Tabbed browsing is nice. For one, as we all know, it is nice to be able to switch between web page sessions in the same window without web navigation. But it is also nice because it allows for more efficient tree traversal of a web site's pages because you don't have to go forward and backwards: once you have expanded a given node (i.e., visited a given page) you can return to it in constant time no matter where it is in the tree (although there is a practical limit of probably around 8-20 tabs, depending on your resolution).