Add markdown support for hidden-until-you-click text (aka spoilers)
Implement the <spoiler> tag
[Apparently I committed some sort of grave sin in *gasp* discussing a potential feature for a proposed StackExchange site in the discussion zone for StackExchange site proposals. Was brusquely told to do it here instead. Anyhoo...]
On IMDB, they cover spoilers as shown in the image below, and it reveals the text when you put your mouse cursor over it. Adding an easy way to do this in markdown would be a great feature for this site.
You can kind of do this already for an entire paragraph with ">!" like this:
However this is a) not obvious to the reader, whereas the above is, and b) is block level only. You can't hide a sentence within a paragraph for instance.
As discussed in the comments, this was closed as the >! mark-up facilitates hidden text. I'll also note that the way IMDB does it and the way SE does it are with very similar CSS properties, so if we really wanted the hidden text covered with a red spoiler warning for a specific site, instead of just being invisible, it would be a very simple CSS tweak.