A spoiler is an element of a disseminated summary or description of any piece of fiction that reveals any plot elements which threaten to give away important details concerning the turn of events of a dramatic episode.
Basically you use the spoiler tags to hide text that people may not want to read before playing the game because it might spoil the surprise for them. Sme people like to know things ahead of time, others like to discover everything for themselves, so it's a courtesy to hide info they may not want to see.
•••Spoiler:Rouce is right.
Spoilers help everyone here, since the discovery advocates don't get their experiances ruined, and those that want to know things can just click it. Is the tag needed here? No.
Just posting to show you how to do spoiler tags.
•••Spoiler:Imoprtant info here •••Spoiler:This is not a sentence
Ok I'm done. •••Spoiler:Not.