How A Keyword Sells A Book On Amazon

In order for a keyword to create a sale through Amazon search, two events need to occur:
1. The book needs to be present in the search results (or rank) for search queries matching the keywords added to the book.
2. The book needs to convince customers (or convert them) to click on a search result, add the book to their cart, then check out (or, make the purchase).

Each keyword creates an opportunity for sales to be made, as each keyword provides the Amazon search engine with an additional way to surface a book to customers. The more keywords assigned to a book, the more data the search algorithms have to work with. Not every assigned keyword will be matched to customer search queries, but you can think of each keyword as asking the search engine: have you thought about showing my book to customers who search for this query? It's up to the search engine to decide, but the more questions you ask, the more likely it will find more ways to return a book.

Behavioural Influence On Search Rank

Once keywords are ingested by Amazon, they’re subjected to a whole lot of parsing and processing, and testing with customers.

First, let’s remember that the goal of a retailer search engine is to maximise revenue, not help people find information (like on Google). This means that on Amazon, discoverability and sales are tightly linked. The rationale behind this is pretty straight-forward - if you show the books most likely to sell,  more often, you’re more likely to sell more books.

Every time Amazon displays a book to a customer in search, the customers’ action is logged. If the action is positive, such as a click on a link to view the product page, a cart add, a purchase or a read on Kindle, it positively impacts the books search rank. The more positive actions a book accrues, the more visibility it’s rewarded with. 

Conversely, if customers don’t respond in a positive manner to a book in a search result, then the book will eventually be outranked by other books that customers respond more positively to.

For example, if a book is shown in search, and the books above and below it are clicked, and not the book itself, this is regarded as a negative signal and will mean the book-query pair will be weighted downward. The book’s search rank for the query hasn’t encouraged positive behaviour so it is penalized.

A simpler way to think of this is - if book A sells more than book B when shown in search, keep showing book A ahead of book B, because book A is making more money. Let’s also try putting book C ahead of book B, and see if that book makes more money instead.

The ability to maintain and grow search visibility is dependent on the book converting through this funnel of customer actions. Sales are the ultimate goal for publishers and retailers, and are a strong search magnifier, but these sales are dependent on conversion.

All of these scores attributed to customer behaviour decay over time, which means momentum matters. It’s easier to improve the discoverability of a book that is already selling and converting well, using keywords, than it is to improve a book starting from low sales.

Conversion And Social Proof

We've all searched for books on Amazon before - you type in a search query and are presented with a list of books. Perhaps you were looking for an exact title, or perhaps you were searching for books about a topic - in either scenario, you might have been swayed to click on a search result if it looked interesting to you.

Think about the factors that persuaded you to click into the book's product page from search. If you were encountering the book for the first time, the only information you would have at that point was the data visible to you in the search result - cover, title, subtitle, price and importantly: the review count and average rating. These last two elements capture the social proof of the expected reading experience.

Social proof is one of the most powerful on-page converters, as customers often trust each other more than the organization trying to sell to them. Reviews are a book’s public record - they convey more value to a reader than whether book it has sold well, and let them know what other people thought about their experience (good or bad) and why.

Reviews are a permanent, mostly unbiased and irrefutable history of a book by it’s readers. And unlike search rank, the social proof from reviews is cumulative and compounds over time - it doesn’t really decay.

Once you have 500 reviews you’ll always have at least that many reviews. With an established positive star rating across a large base of reviews, it’s also highly likely future reviews and ratings will follow a similar pattern, further strengthening the book’s ability to convert.

In a future post, we'll analyse some data to see how social proof relates to search visibility on Amazon, including examples where Top and Recent customer reviews have been impactful. But in the meantime, thinking about a keyword's place and ability to influence a sale in the search funnel, will help you to focus on which element of metadata to prioritize to maximize sales potential.