Who was the person who decided that tabs have to stay on the top or the bottom of the browser or application you are using?  In Firefox the default spot is the top but it does not have to be.  With the Tree Style Tab extension from Firefox you can add it to your side and also give it a tree like appearance.

Now does that mean it will be green and brown?  No, not exactly.  Think of it much more as a folder tree like you would see your folders in via Windows Explorer.  New tabs are opened from links and attached to the current tab.  If you have tons of tabs open this will help you figure out which tab is associated with which topic you are browsing about.

Some of the features of Tree Style Tab include:

• You can collapse/expand sub trees. It is convenient for too many tabs.
• When you close a tab which has collapsed sub tree, all of tabs in the sub tree will be closed only one action.
• The tree of tabs can be show in at right side.
• Vertical tab bar cab be shown/hidden automatically.

If you have been wanting to find a way to give your tabs a new look and feel or you are looking for a way to better organize the tabs you have open Tree Styled Tab is an addon that can not be overlooked.  It gives you a unique experience just by making one simple change to your browser interface.