Milk chocolate and White chocolate have a limited shelf life. Dark chocolate will last indefinitely when foil-wrapped and stored in a cool, dry and dark place. Dark chocolate needs to be tempered to make it look shiny and taste more palatable. White chocolate sometimes does not contain cocoa butter.
Confectionery coating (a.k.a.: summer coating, candy melts, coating chocolate, etc.) contains vegetable fats instead of cocoa butter, and tastes somewhat similar to chocolate, but it is not true chocolate.