I hate to ruin it for you, but Darth Vader is Luke Skywalker's father.

At what point do major plot reveals and the like cease to be considered to be rude to let loose?

I think once a year or two has gone by, or when a sequel comes out, it's fair game.

Never.
Just cause a films old doesn't negate the twist or reveal. Imagine if someone spoiled the end of The Thing or The Usual Suspects before you'd got round to seeing it. If they don't know, let them discover it for themselves.

Spoilers should always be prefaced by some kind of alert...

...Assuming it's not something that's ingrained in public consciousness, such as King Kong or Passion of the Christ...

It really depends on how popular the spoiler is.

"Aeris Dies" is so popular that everyone knows about it, so it's ok.

But something like (Cowboy Bebop related)

z121231211:
"Aeris Dies" is so popular that everyone knows about it, so it's ok.

...Who's Aeris?

EDIT: This actually isn't a joke by the way. I have no idea who this Aeris is.

Anyway, I agree with The_Deleted that you shouldn't spoil things as people might want to go back and discover things for themselves.

Probably one or two years. If you really cared about what ever it is, you most likely would know the spoiler by then.

Apparently, Dumbledore kills Snape. Or so I've heard.

"Hey! Snape kills Dumbledore!"
"NnnnooooooOOOoooo!! You BITCH!"

It's actually unable to be measured in years so directly like that.

Upon release, and while the movie is playing in theaters, along with anywhere from a year to a few years after a movie is released to video or DVD or whatever, (note, just movies here) are spoiler-tagged.

After that, if the movie doesn't sell all that well, or isn't popular, it's still spoiler-tagged (so those niche film people can still watch it). However, if the movie was wildly popular, it can be non spoiler-tagged at one's discretion.

It remains this way for, say, about a generation. After that, it must become spoiler-tagged no matter what, so those in the new generation may go back and watch it without the story being ruined.

If, however, the movie is along the lines of the Star Wars "luk i iz ur fatr" in its big plot reveal, it can remain non spoiler-tagged.

That's for movies.

Books and games must always be spoiler-tagged.

I know somebody who made a review for star wars: TFU and ruined the ending in the first 30 seconds. This was about one week after relase.

Never.

As long as there is something with a really good spoiler-worthy moment, there will be people yet to experience it. So even just saying 'Snape kills Dumbledore' could ruin a whole series of books for someone, which is just mean.

I'd say more a major hollywood release something like 1-2 years at the absolute max. Off the beaten path series (like Cowboy Bebop) or vaguely obscure films (Fallen) with fantastic twists shouldn't be ruined.

As for Lost or Heroes I actively encourage everyone to ruin it for everyone else because, especially with Lost, they've become so damn reliant on twists.

EDIT: OP, good thread idea.

It can't be measured in years, but rather how known something is. As a general rule I'd say never, unless it's something that is public knowledge (or should be). Shakespeare, 1984, Star Wars, Lord of the rings, etc, people should know. They have shaped literature and movies as we see them today and should be part of the common knowledge.

If it's not, then it should be it shouldn't be spoiled for people.

I'm really into UFC. Whenever I meet another dude that's into UFC and they've seen the most recent UFC and I haven't, they inevitably ruin it for me.

Once, I met a dude and we were talking about UFC and he asked if I'd seen the most recent one and I told him that I was going to watch it the next day. He immediately started telling me how awesome it was and I threw my hands up and asked him not to say anything about it and especially not tell me who wins any of the fights. He said, "OK, but I'll just say that it's awesome and all the fights go all three rounds and the title fight goes all five rounds."

I was so pissed. He basically ruined every fight for me by telling me that. That means any time someone is trapped in a submission hold and it's not the final round, I know he escapes from it. When they're standing and striking, I know there's not going to a knockout or ref stoppage. He was a nice guy and had no idea what a dipshit he was, so I didn't feel justified chewing him out. I'm still a little pissed thinking back on that.

I think it's ironic that a topic about spoiler etiquette has so many unmarked spoilers in it.

Here's a cool T-shirt that's very much on topic:
http://www.threadless.com/product/844/Spoilt

DrunkenKitty:
I think it's ironic that a topic about spoiler etiquette has so many unmarked spoilers in it.

http://www.youtube.com/watch?v=hN5avIvylDw

Might as well spoil them all :D

Unless it's something like the Starwars example then it should be spoilertagged, and and even in common knowledge scenarionos put spoilertags just for safety. And could there please be no more spoilers from this point on. Nothing have been ruined for me yet, although I got scared and exited the thread when I saw The Usual Suspects mentioned as I've yet to see that film and I have already had The Sixth Sense ruined by the Internet.

ZenMonkey47:
I hate to ruin it for you, but Darth Vader is Luke Skywalker's father.

At what point do major plot reveals and the like cease to be considered to be rude to let loose?

Knowing the twist of a film or game ruins the possible experience. If it's a film widely enjoyed, to even know there is a twist ruins it because time is spent looking for the twist rather than enjoying the story.

However, if the film is generally thought to be crap say American Psycho 2 (the writer(s?) of which completely missed the point of the film they followed and the book that film portrayed) any kind of disclosure is fine.

rossatdi:
I'd say more a major hollywood release something like 1-2 years at the absolute max. Off the beaten path series (like Cowboy Bebop) or vaguely obscure films (Fallen) with fantastic twists shouldn't be ruined.

EDIT: OP, good thread idea.

Would you willingly tell people who Keyser Soze is if they didn't know?

BTW. Fallen was excellent.

In closing, if in doubt, never mention a twist.

It really depends on the situation, and unfortunately is left to discretion. For the most part though, I think it's courteous to avoid potentially spoiling anything that can be spoiled, regardless of age. Of course, it happens occasionally to everyone, sometimes people let something slip out. But some common sense in the matter goes a long way, DrunkenKitty's post is a perfect example of someone using zero common sense and at the same time not realizing he was ruining anything.

In general, I just try to keep in mind that no matter how popular something may be, not everyone has seen/played/read it. Of course, as has been pointed out, there are some things that are just so big a part of popular culture that it'd be hard to find someone who doesn't know about it. The "Luke I am your father" bit is a good example. Who hasn't heard someone say that in their best Vader voice?

A couple weeks back at work we were out on break, and one of the guys asked if anyone had seen the new Bond movie. The other three of us standing there all responded that not only had we not seen Quantum of Solace, but none of us had actually seen Casino Royale either. He proceeded to tell us the ending of Casino Royale and how it tied into the next movie. We all stood there, looking at each other dumbfounded, and shook our heads. The only excuse I could think up in my mind was that he just doesn't care about things being spoiled for him, and isn't bright enough to realize that others might.

MrGFunk:

rossatdi:
I'd say more a major hollywood release something like 1-2 years at the absolute max. Off the beaten path series (like Cowboy Bebop) or vaguely obscure films (Fallen) with fantastic twists shouldn't be ruined.

EDIT: OP, good thread idea.

Would you willingly tell people who Keyser Soze is if they didn't know?

BTW. Fallen was excellent.

In closing, if in doubt, never mention a twist.

I'd probably not but I wouldn't consider it terribly 'major'. I heard the spoiler to Fight Club before I saw it but I loved it anyway. I think it really comes down to if the twist is central or not. For example Se7en. I don't think giving away that Kevin Spacey is the killer is a big deal. I certainly wouldn't say anything about the final twist though...

rossatdi:

MrGFunk:

rossatdi:
I'd say more a major hollywood release something like 1-2 years at the absolute max. Off the beaten path series (like Cowboy Bebop) or vaguely obscure films (Fallen) with fantastic twists shouldn't be ruined.

EDIT: OP, good thread idea.

Would you willingly tell people who Keyser Soze is if they didn't know?

BTW. Fallen was excellent.

In closing, if in doubt, never mention a twist.

I'd probably not but I wouldn't consider it terribly 'major'. I heard the spoiler to Fight Club before I saw it but I loved it anyway. I think it really comes down to if the twist is central or not. For example Se7en. I don't think giving away that Kevin Spacey is the killer is a big deal. I certainly wouldn't say anything about the final twist though...

Don't you consider the Usual Suspects to be a bigger part of the story to Se7en though?

The Se7en twist was "Oh, okay then."

With Usual Suspects and Fallen both reveals change parts of the story you just watched and therefore your perception of the film. What do you think? Does this mean twist are relative?

Also, other people have mentioned the sixth sense I don't consider this reveal to be a twist because it's spelt out all the way through. It's not a twist. It's the story.

I still don't think I'd reveal it because I did ruin Usual Suspects for someone and 12 years later I still hear about it. This may have effected my opinion on spoilers.