For example, I have seen reference a time or two to a parallel set, but I don't know what that means.
There have been initials that I looked up and the glossary told me what they stood for, but I didn't know what the terms meant.
I have things that the site was missing, and along the way have been learning by asking. I guess my greatest concern right now is the definition of the set types.
Insert (Not sure of the scope here. Is it every type of subset a package may contain? Stickers, holograms, autographs, any subset you may find in a pack?)
Mail-In (This is sort of selff explanatory, I had to mail in to get it)
Parallel (Don't really know what this could be.)
Promo (I'm getting a handle on this, it tends to be a pack in somewhere with no official numbering on it, Sort of an incomplete card meant to advertise a coming set)
Proof (Not entirely sure but this is sort of self explanatory, and I never expect to encounter a card such as this anyway)
Not a true card collector, but at times have collected cards in an ancillary manner to other interests.