Search Suggestions is a feature launched in 2006 enabling anyone with an Amazon account to add a bit of human intelligence to the site's search engine. On each book detail page, the link Make a Search Suggestion allows users to recommend tying a book to specific keywords. Users also explain why the keywords are relevant and will help people find the book.
One way for an author to take advantage of Search Suggestions is to link their book with relevant words and expressions that don't appear in its title or subtitle, or perhaps even the full text. For example, let's imagine you've written a book about predicting hurricanes. A year after your book goes on sale, the most damaging hurricane in history, a storm named Zelda, devastates the Florida coast. By entering the Search Suggestion "Hurricane Zelda," more buyers would find your book, even though it didn't contain "Zelda."
Once your Search Suggestion is approved, when customers search using your keywords, the book appears in search results along with your relevancy explanation.
For example, one Amazon customer submitted a search suggestion for Shakespeare's play Macbeth. Now Macbeth appears when customers search for "The Scottish Play." The relevancy explanation is shown next to a link to the book: "Theater superstition dictates that 'Macbeth' is referred to as 'the Scottish play.'"
Another example: Searching for "stolen data" now returns the book, I.T. Wars: Managing the Business-Technology Weave in the New Millennium.
Adding human intelligence to book searches could be a big help for finding material in niche topic areas. However, it seems a feature like this could be misused by spammers and practical jokers, so it will be interesting to see whether Amazon can police the system effectively. However, several types of Search Suggestions are prohibited:
Profanity, obscenities, or spiteful remarks.
Commenting on other search suggestions (other suggestions and their position in search results can change).
Phone numbers, mail addresses, URLs.
Availability, price, or alternative ordering/shipping information.
Time-sensitive material such as interviews or concerts.
Suggestions that may be "controversial, politically or otherwise."