Don’t spoil it! Hide anything with a bit of blur. Hint on mouseover. Reveal on click.
In your posts, you can surround text or images with [spoiler] … [/spoiler] to blur an answer.
For example:
I watched the World Series on TV last night. The Cubs won.
–or–
Justin Verlander is pitching in the 7th inning right now. He’s throwing a no-hitter.