Butchie, you've touched on an issue that gets almost as divisive as politics!

There's a firm, for example (which I will leave un-named) that has agreements with many small countries allowing it to print stamps in their names. They produce ridiculously large numbers of stamps that never see the light of day inside the named country, and cannot be found validly used as postage. A lot of collectors call the stamps "wallpaper". Now... are they official stamps or just junk? Scott says junk. Other catalogs include them. It's up to the individual, I guess, in the end.
For me, when I use the term "cinderella", I'm usually referring to stamps that never had pretensions of being
postage stamps... old advertising or patriotic labels, for example. National Wildlife Federation stickers are a nice example, too. That field is nearly infinite and a lot of fun. I admit (and this is just me) that stamps pretending to be postage kind of annoy me.