Custom Version of Android
What is a "Custom Version of Android", AKA ROM
Maybe all this words are new for you. Don't worry, we'll explain them. As we just said, once you are root you are able to change the ROM (or custom versions of the Android) of your phone. What is it? Basically is a modified version of the stock Android ROM in some way enhanced. Normally, ROMs are faster, lighter, with less energy consumption and with different looks.
But one of the main characteristics is that you can install a different version of Android that is not out yet. For example: install Android 4.0 in an LG phone or Android 2.3 on a T-Mobile G1. If you are more interested in this topic, check out this uperb guide from Android Police.
But basically we just wanted to make one thing clair: RRooting is not the same as changing a ROM. Rooting is the first step in the process ofchanging a ROM.