Spoilers

Saw an article a few months ago that claims spoilers actually improve the reading experience. I couldn't find the original article, but this one has a good summary of it.
http://news.yahoo.com/spoilers-stink-study-says-plot-doesnt-matter-200000797.html/

What do you think? Something to keep in mind while editing? Could make the first chapter a huge spoiler chapter (with appropriate warning), but where's the line between doing that and foreshadowing...

Well, yes and no. Some things I have been encouraged to explore precisely because a spoiler revealed something about the plot that made me interested in it. But also, spoilers are spoilers and it can make something ponderous and unrewarding if you're just waiting for what you all ready know will happen.