What is the TRUE definition of Replayability in gaming?

[Veknoid_Outcast]

I think it's about multiple playable characters, multiple classes, unlockables, multiple endings, multiplayer modes -- all things that would bring a player back after his or her first playthrough. I don't believe a game's "fun factor" should count toward its replay value. For example, Shadow of the Colosuss, despite its greatness, doesn't have high replay value. Infamous, with its branching morality paths, collectables, and upgrades, does score extra points in that category.