Beta versions of the new Mac OS X Lion have been passed around and people who have had the option of a thorough hands-on with the software have started to report back. One of the features that was stumbled upon is the "Restart to Safari".
macrumors.com - Many of Mac OS X Lion's features have been known for months, but Apple has snuck in at least one interesting new feature called "Restart to Safari". On Mac OS X Lion's user lock screen, you are given the option to "Restart to Safari" rather than logging in. This allows you to boot the computer into just the web browser and nothing else. This browser only mode allows unauthorized users to simply browse the web through Safari rather than having access to any personal files or other applications on the machine.
Obviously parallels can be drawn with the Chrome OS from Google that functions in a similar way. But the usability of a web-browser OS coupled with a full OS to boot has never been tried out before. We will have to wait till Lion OS is officially launched to see how Apple intends to implement this feature on their machines. The full story can be found here.