NEW YORK - Rosebud is a sled.

So goes the ending of the 1941 Orson Welles classic "Citizen Kane," spoilers be damned!

Revealing secret endings and plot twists has brought on wrath since the dawn of cinema, straight through VCRS to today's DVR-fueled delays that led to much nail-biting over The Ending That Shall Not Be Spoiled on "Breaking Bad."

But exactly what is the magic formula for spoiler grace? When do calls of SPOILER ALERT (insert index fingers in the ears here) expire so we can, maybe, not feel so constipated when discussing our favorite fare in real time?

Does the 13-episode Netflix dump of "Orange is the New Black" in July equal two months of polite spoiler-free behavior? Are bets off when a show concludes, or does that depend on how many seasons late adopters would have to slowly, slowly slog through - say Dexter's eight to Breaking Bad's five?

Or is it up to the unspoiled viewer to avoid social media or catch up? Get it done, people!

"I think asking people not to spoil for some reasonable amount of time is fine, although anyone who actually takes it seriously, i.e. gets mad or upset in the event someone does, is an idiot," said technology analyst Melanie Turek in Steamboat Springs, Colo.

"But that 'reasonable' amount of time is, in my mind, about 48 hours after a live broadcast," she explained. "And once a series is off the air and the hype has died down, asking people not to spoil is just silly."

Others think keeping some things quiet - or at least warning our Facebook friends about potential spoilers - is what 21st-century etiquette might advise. At least that's what the ragers who decry spoilers on social media hope for.

Marketer Kim Puckett in Indianapolis thinks "we're all social media-level entertainment reviewers now" so should respect our written-word audiences on newsfeeds like Twitter or in status updates on Facebook that aren't easy to escape.

"Unfortunately, specific status updates on key plot points might be banned forever," she said.

But in other contexts, Puckett said, "as soon as the show ends, office and social talk should be allowed about the show. How can we enjoy shows at a social level if we're always worried that someone is still on Season 1 of 'The Killing' or halfway through 'Sons of Anarchy?'"

Justice is on the side of those who want to blab on Twitter or Facebook, according to Paul Levinson, a professor of communications and media studies at Fordham University and author of the book "New New, Media."

The idea that "people have a right to be free of spoilers is absurd, and it's an absurd misuse of the term 'right,'" he said.

"You have a right to communicate," Levinson assured. "I don't think anyone is entitled to that kind of grace. If you feel like writing something you're entitled to write it as long it's not slanderous or libelous or breaking the law in some way. Why anyone would get into a rage about entertainment is beyond me."

He harkened back to buzz over "The Crying Game" and Dil's reveal as a transgender woman, along with "The Sixth Sense" and the Bruce Willis character being dead. And there was grumbling over spoiling the purgatory at the end of "Lost," at a time when social media was well on its way to engulfing us, he said.

"If the ending is really atrocious, like 'Lost,' then you're probably doing people a favor by letting them know," Levinson said.

Etiquette expert Lizzie Post of the Emily Post Institute sees no value in people "posting a million times, 'Don't spoil anything for me, don't spoil anything for me.'" Walk away from Facebook, shut down Twitter if you have to, she said.

"If you're not living in the current season you have no claim. It's fine if you have a friend who's really into it and you want to say, 'Don't spoil it for me.' But you can't ask the world around you to completely bend."

Has the quality of conversation been damaged by the call for spoiler-free discourse?

"What we've lost is the ability to step back and assess what we've just seen," said Danny Glover, who like Puckett is in marketing and pays close attention to social media. "I think overall the live conversation is valuable."

Judith Martin, who writes the Miss Manners columns and books, also believes the burden falls mostly on the person holding out for the surprise.

"But if the story is really good, it shouldn't make that much difference," she said. "I still enjoy re-reading 'Moby-Dick' and 'The Golden Bowl,' even though I know perfectly well what is going to happen."