From Wikipedia:
"A snob, guilty of snobbery, is a person that adopts the world-view that other people are inherently inferior for any one of a variety of reasons including supposed intellect, wealth, education, ancestry, etc."

An inverted snob is therefore the opposite: One who adopts the world-view that other people are inherently superior etc etc.

I think Diane used the expression because you were self-effacing i your recent long post - no doubt she'll correct me if I am wrong.