Firefox is not able to remember where you left off the last time you were using it. This is normally not a big deal if you are able to close firefox after you´ve done what you wanted to do. The problem begins when Firefox crashes or when you have to turn off your computer in a hurry. Session Saver is able to save the current state and restore it at a later time. Session Saver saves tabs, window positions, text in websites and cookies for example
This is not only great to prevent data loss through crashes but also nice if you have websites that you visit together. Say you have a set of three websites that you visit once a day regulary. Save the session when all three websites are open in their own tab and restore them the next day right where you left oft.