Internet Explorer 7 when running on Windows Longhorn, will run in reduced privilege mode by default to reduce the possibility of Spyware and Virus infection. Running under a root or admin account is one thing that Linux and other Unix look-alikes have strongly frowned upon almost since their inception. It is also a practise that Microsoft has encouraged in Windows by setting new users up with administrator privileges from the get go in most versions of Windows. Apparently that will change when the next windows release finally comes out sometime next year.
Internet Explorer 7 will NOT be available for Windows 2000, and only XP SP2 and above platforms will be supported. The XP installation will also not make use of reduced privilege mode. Anybody not running one of the supported Windows versions can install and use Firefox to get a comparable browsing experience without the cost of an Operating System upgrade.
Is it just me, or is Windows becoming more like Linux/Unix at the back end with each new release? After years of seemingly ignoring the problems that running as admin causes, they have suddenly decided that Linux/Unix developers were right and reduced privilege modes are good.