Post spoiler warnings if you are giving a crucial detail of a movie. Some moderators may see something as crucial, others may not, so be safe.
Use the spoiler tags that we have [.spoiler] put your spoiler here [/.spoiler] (without the periods before spoiler, they are only there so you can see the tag.
Spoiler: (Highlight this box to see the hidden message.)
High light that to see the spoiler.
If you abuse this feature, especially in other forums, you will be banned.