Books are ranked within each category in terms of their popularity, or what we also refer to, internally, as a book's "temperature" (think of it this way: a book that is HOT, has a higher temperature than a book that is COLD)
The HOTTEST book is given a ranking of 1. Rank 2 is for the second hottest title.
In some cases, particularly for titles that haven't had any sales, the ranking is a reflection of where it sits in terms of its category. For example, if there are 1000 titles in a single category, a title that hasn't sold anything will start off with a ranking of 1000. There might actually be a dozen titles all with that very same ranking as they all share the same temperature of "nothing"
This basically means that even a newly published book that hasn't had any sales will still have a relative "temperature" in its category.
- Rankings (or "temperature" achieved not solely based on raw sales alone. The ranking is based on a combination of sales as measured within a particular time frame, number of clicks, and involve complex algorithms. That is to say, a book that gets HOT really quickly but then has no other action, also COOLS quite quickly as well. A book that sells consistently over a longer period of time might maintain an overall higher "temperature" than a book that shows a single days of sales.
- Ranking is extremely dynamic and a book can move through dozens of different rankings in a single day, and that, some days (days in which there happens to be a flurry of sales activities, ie, during promo periods, "Black Friday" or Boxing Day, for example) the fluctuations might be more vivid than on other days.
- Your book might have multiple temperatures in different Kobo regions. (If you click on the country flag at the top of the website, you'll see that you can change the view to see your book from another country's perspective) - For example, your book's ranking in the USA might be different than the ranking in CANADA or in AUSTRALIA or in FRANCE or GERMANY or some other global territory. IE, if all of your sales are coming from CANADA, then the "temperature" of your book in Canada will be higher than in another country.
Beyond the ranking within a category, Kobo also tracks the TOP 50 to reflect the OVERALL sales in the highest level of popular categories (such as OVERALL, Romance, Mysteries & Thrillers, Sci-Fi & Fantasy, Fiction & Literature, etc) -- and, like the temperature within a category, each country has its own unique TOP 50 Ranking.
- The categories shown on site for your book refer to the ones that you selected when entering your metadata. Clicking on the category name that you see beside the ranking brings up the ranked search results. The book’s ranking may differ in this list from the number on the web page as it can take our search results a while to catch up to the data on our system.