I love reading rules for spoilers. Working out an etiquette for when, and where, and how much it's okay to talk about art that came out recently, or art that isn't too popular, isn't the biggest ethical debate on the internet. It's not the biggest problem posed by the changes in media over the last ten or twenty years. But, maybe for that reason, I think it's the most fun. Slate is tackling this question specifically as it relates to the new Netflix original series, House of Cards. House of Cards was released all at once, today. There are 13 episodes, apparently 1 hour each. It seems to me that makes this show, as far as consumption etiquette is concerned, more like a book than a TV show or a movie.
Sam Adams, the author of the article, draws a distinction between "Push" and "Pull" messaging that I hadn't thought much about before, and that I really like. Posting on Twitter or putting a spoiler in a headline is a push. writing in the middle of an article or deep in a comment thread is a pull. I feel I was intuitively aware of this difference, but it's nice to see it spelled out.
The usual discussion of expiration dates turns up in the form of "by next Thursday, it’s fair to expect that those who care most about not having any detail of House of Cards revealed in advance will have worked their way through the entire thing."
The other two bits are just basic rules about life and art: Don't be a jerk, awesome advice, and great art can't be spoiled. Or, great art can't be ruined by spoiling. It might lose a little bit, but experiencing a good story is worth it even if you know how it ends. Nobody watches a show just waiting to find out what the last plot point is.
Relatedly, Slate is starting a podcast explicitly about spoiling movies for the purposes of discussion. Now, they're doing Warm Bodies. If you've seen it, check it out.