User blog comment:Mira Laime/New Page Header on Discussions/@comment-27938131-20170813202222/@comment-26339491-20170814221002

That's a good point! We'd love to add a feature to Discussions that would let users hide spoilers in their posts. It will still be quite some time until we can be sure there is room for that in our plan, though. We want to finish the other updates I described first.

For now, the only way that can be done in Discussions is to have a separate spoiler category, and anyone who wants to avoid them needs to filter out that category.