rooting allows superuser permission.. some apps in the marketplace require it.. only way to get this.. is root! it basically allows you to download and install pretty much anything to the phone were as is if its not rooted you are limited to what your able to do.. mainly system apps, things that will change or effect the way your phone operates.. etc. for example try to download setcpu in the market, it will tell you for root users only, if you download it and try to run it, it will say the program was not granted superuser permission..theres a app for the vibrant called OCLF.. its in the market, it will allow you to root and install the lag fix very easily to your phone, then you can install a wifi tether app cause they usually require root.. my vibrant runs a quadrant score of around 2500ish.. its rooted, lag fixed and overclocked to run at 1.2Ghz..