MoSCoW prioritisation is a method for collating all your features, user stories and feature requests into an sense of order, identifying what is most important and therefore should be delivered first or given the most concentration, within software development projects.
My particular umbrage with MoSCoW is the “Won’t have”. In my opinion this is wrong, it’s negative, it dismisses features or requirements because there isn’t enough time to complete them all. A perfectly valid viewpoint I hear you say – but in my experience dismissing any feature or requirement at the stage of a project wherein you would use MoSCoW is far too early to begin dismissing anything.