OK....I haven't had PS for very long, and I know that masks are very useful , but I don't know why! Anytime I've thought about using a mask for anything I've thought, "Why not just use a selection?"
Obviously, I'm missing the point completely somehow, so can anyone explain why masks are so valuable and if possible give me an example where using a mask would be better than selecting?
Thanks!
--NN
They are not mutually exclusive, and in my opinion you'll have more flexibility if you use them together.
Masks are especially helpful if you are editing on a layer, as they more easily allow you to change your edits.
One time-saving trick is to use a selection tool to select the area you want to mask off, then add a layer mask. The mask is instantly created using your selection, and you can fine-tune it.
Here is a good tutorial on masks:
http://www.etsu.edu/oit/ats/metatraffic/...%20230.pdf
And here is a very simple example using the gradient tool to create the mask:
http://www.grafx-design.com/01photo.html
Pretty similar, I think, but with subtle differences. With microsoft digital image suite - selections are limited in the fact that you can only select using spefied shapes and using the lasso type outlining tools. With masks you can use painting and brush tools to get the areas you want. Masks also let you see the selected area more easily...
Thanks for the links, an interesting read.

Thanks Slej....Those links are very helpful and it's now making sense (at last!).
--NN