I can certainly relate to this, when ever I'm yet to see an episode from a famous show I have have to be very careful to avoid spoilers on Facebook, Twitter, Reddit from the day since the show was aired.
When ever I see the show's name being mentioned, I squint my eyes and scroll as fast as I could! I guess it applies to famous movies as well.
Ad blocker cannot be used in these social network sites, as the posts are random and even if it works; we cannot block pages, subreddit, permanently as most of the times I do watch the episodes/movies on time and I would like to interact with those who mention it.
So, what we need is a solution where we can easily toggle the spoiler blocker.