"Glazed" Discs

[The Monty]

Have just looked at my rotors and they appear to have taken on a "Glazed" type looked, almost as though they have been hit with a polishing wheel. Im guessing this is what people call Glazed disks, but my question is, does it affect your rotors, how do you get them looking unglazed, and what causes them.
If anyone needs to know, the car is an AU1 Fairmont, and I do a lot of mountain driving.