In English Grammar: Meryn Stol voted up this answer. Anonymous It's a somewhat obsolete way of saying "Oh!  Thank you!"  It's more heavily associated with the 1950's and before, and is generally used self-consciously in a somewhat silly/flirtatious way.  If you got this response after asking someone out on a date, it's most likely a very good sign. See question on Quora - Meryn Stol