"The secret of being a bore is to tell everything."Spoilers are our stock-in-trade here at TV Tropes — you can't talk about stories and plots without revealing the details of the stories and plots, which might ruin the experience for people who haven't yet had the chance to view that work. To combat this, we have the spoiler tag markup [[spoiler:some text]]. However, this presents a problem. Virtually all examples are going to be spoilers to some extent, and we can't blank the entire wiki on the off chance that someone will be spoiled. One of the big draws of a site like this is simply browsing from one page to the next and absorbing the information therein, and that appeal is lessened if every interesting fact is lost to the fog of a spoiler tag. So, over the last ten years we have developed a few very simple rules about using spoiler font:
Okay, that's the policy part. Now we can talk about something that bugs tropers who have an interest in making things look good: Swiss-cheese entries, entries where single words and short phrases are cut out and other text is left visible. Face it, it looks like crap to people who have the spoiler font blanking effect turned on, which is the vast majority of the readers. It is the default. Having specific rules about what to hide in the example is too complicated. It boils down to: Think about it. Think about the casual reader, who doesn't care about spoilers. We know it seems important to fans of a given work, but the far and away majority of readers are not people with a fannish mindset at all. We who edit are mostly fannish, but the people who edit are less than 1% of the people who read the wiki. Let's continue to write for the casual reader. It is our best way to convert them to fans. Finally, avoid Wicks and Potholes in spoiler tags, because mousing over them reveals what's beneath, making it pointless to conceal them. Plus, they stand out in some browsers.
There are some special-case rules for not using spoilers in the Spoilers Off page. But, please, if you don't see your specific case listed there just use your head and favor the needs of the casual reader.