Very interesting reading:

Jouni Smed & Harri Hakonen: Towards a Definition of a Computer Game.

Interactive entertainment means games, says Greg Costikyan. Even though I do respect his reasons for saying that, I must admit it is a fallacy.

We have to ask ourselves this simple question: Does there exist any kind of interactive entertainment which is not a game but still interactive entertainment? Well, the answer is simple: chat!

Whether it is on the radio, television, electronic chat on the Internet, or even RL, we do find chatting amusing and it is certainly interactive.

Although, chat may be play-like, it is not a game.