Basically rooting means, gaining access to the core files and folders of your phone that you normally would not be able to touch. By having access to those files and the access to alter them, this allows you to change appearances, functions, CPU speeds, and add goodies to the operating system of your Droid. And for those of us that are not talented in computer programming, lol, which is most of us, you can install already modified versions of the operating system that some very talented developers have created....hence the Bugless Beast ROM you mentioned...