Remember: with great power comes great responsibility.
(You have no idea how long I've been wanting to use that line in a post).
Just because you can post a spoiler doesn't mean you should. Repeat it, learn it, make it your mantra. When you are excited to tell the world about the insane scene that just aired on Game of Thrones, restrain yourself. Sit on your hands. Phone a friend you don't like. Don't put it on Twitter or Facebook or Tumblr to slap the world in the face.
Sometimes I want spoilers. I want to be the one to go dig them up. It needs to be my choice. When Battlestar Galactica was airing, I spent an inordinate amount of time on the LiveJournal Battlestar Blog community reading theories and leaked spoilers. When I couldn't watch episodes the night they aired, I'd log on with the desperation of a dehydrated maniac and read the episode summary and analyze the main events. Even so, the spoilers were politely put behind cuts. You had to actively click on a link to face the spoilers. It was hard to do by accident.
But now. I visit my Twitter feed within five minutes of a show ending on the East coast and some tool is posting the ending. How long should you wait to post spoilers? My advice: if it is that hard for you to contain yourself, find a forum or specific chat room where everyone's on the same page. Or episode. After a particularly frustrating experience after Game of Thrones, someone mentioned - "well, I at least wait until it has aired on the West coast." Here's a crazy thought: not everyone gets to watch a TV show the day it airs. You can't put Twitter or Facebook or Tumblr behind a break. You are forcing your spoilers down the throat of anyone who follows you, and damnit it's rude and inconsiderate.
This has been a public service announcement.