If you are a ardent web surfer and you use firefox mostly for web browsing,then this article could be interesting for you.
It is very common for a web surfer to open more than 9 sites in a firefox in the same window, it happens to me as when I browse through large number of blogs and web sites opened in different uncountable tabs.
Switching across these tabs becomes more and more difficult when as number increases, so there a key board shortcut associated with each tab starting from left as ctrl+1 for first tab, ctrl+2 for the second tab and so on..
source and more : firefox tips
