I agree with the previous poster, Upgrades are rare, but you usually only hear those people post who get them. I was under the impression that it would be easy to get an upgrade, but in the four trips and 7 resort stays at WDW, I have never been upgraded. However, When politely faxing in special request for views and room location, I have always received that!
Goofy4Tink - I think the reason why hotels offer upgrades is because they want to make their guests feel special whenever they can. Especially at WDW that is very much apart of the "Magic" everyone refers to when going there. Why not make a guest happy by offering them an upgrade on an otherwise unsused room if it is available? They lose nothing, and the guest will have a positive experience that will more likely than not mean a return visit or at the very least - good word of mouth.