I found here in the spoilers paragraph that putting >! would hide the following things, which was a way for me to alleviate a question's heavy presentation by hiding paragraphs that could be seen if and only if details are needed, but using >! did not work... (See here.) Where is my error, and is it indeed possible to do this with >!, or with an other sythax?
As Emil Jerabek has already written in a comment, hiding a paragraph actually works if you put the >! at the beginning of a line.