A cool new example:
The fansite Tower of the Hand has developed a unique, and uniquely user-friendly, approach to spoilers: a “scope” system in which readers select the point they’ve reached in the series (book or show) using a toggle bar that hides or reveals information in the article they’re visiting according to their selection. By tagging different sections of each article according to the corresponding source material—”Book 1,” “Book 2,” and so on—site co-founders John Jasmin and Alex Smith are able to customize their reference materials, reviews, and essays to the needs of each individual reader.
The Dish 