Hey I know exactly what you mean, I'm always in constant disbelief at the amount of people who look up spoilers for Doctor Who, I mean I saw one forum full of people dying to share the finale secrets for the current season, before the season had even started! I hate being spoiled. It's such a waste, and such a showing of impatience and greed.
When it comes to LOST, I've come to know that the trailers they put on at the end of each episode are often strongly warped slices of the real deal - the next installment. It's become an obsession to stress over what the next trailers' footage actually means in the time between episodes, just as much as it's another obsession to stress about the most recent episodes' content too. 95% of the time I'm wrong in so many ways with my theories and I'm still having WTF moments every episode, stories I didn't expect to start or end, etc. The trailers are where I draw the line, it's the folk who like to know it all before broadcast that startle me.