LCD's do not suffer from "burn-in". Although Apple may call it "burn-in" (just because it appears to the consumer to be the same thing), it is not. What is actually happening is called image sticking. It is from the liquid crystal molecules (somewhat) reorienting the polyimide alignment layer while the LC molecules are held in a particular position (under applied electric field). When the field is removed, the LC's prefer this previous image, as the anchoring condition has changed. The "solution" as Apple states, is to turn off the monitor (zero-field) for about the same amount of time (or longer) it was left in the "burn-in" state. This is to cause the LC to reorient the polyimide in the zero-field state back to restore the initial anchoring. In summary, LCD's do NOT "burn-in" but they can exhibit image sticking (especially if the polyimide is not completely cured (or solvents aren't removed)-generally an issue with QC during manufacturing). Plasma displays however, DO burn-in and there are various tricks to get around this, or at least to fool the eye by uniformly burning in the area adjacent to the fixed graphic such as wobulation. I hope this clears things up.