Amazon has long featured bestseller lists track sales ranking by the hour, but what the e-commerce giant has lacked is a weekly list. That changed this week with the launch of Amazon Charts, a new feature that will include not only the top 20 bestsellers at the retailer in both fiction and nonfiction, but also the 20 most read books in both categories. Adult books and children's books will be included on the lists.

The "most sold" chart will rank bestsellers based on aggregated sales (including pre-orders), as well as books borrowed. Sales will be based on activity from all of Amazon’s platforms (Amazon.com, Audible.com, and Amazon Books), and across all formats (print, digital, digital audio and books read through Amazon's subscription services).

“People are reading differently now, and we want our lists to reflect that,” said David Naggar, v-p of Amazon.

The "most read" list will be based on titles read, or listened to, via Kindle devices and Audible. Naggar thinks that feature will reflect "what is going on in the zeitgeist" more than Amazon's lists based solely on sales.

Both lists will be unconventional. There is a buy button on each bestseller, as well as an icon that lets readers view a few pages of the book (via the company's Kindle Instant Preview technology). Other features are intended to provide fun insights into the books on the list; Amazon, for example, will tag books as that its data indicates were "unputdownable."

Naggar said he ultimately sees Amazon Charts as another tool for book discoverability at the retailer.

The charts are available at amazon.com/charts. The list for the week ending on Sunday will be posted on Wednesday. Naggar said elements of the charts will also be incorporated, in some way, into Amazon's bricks-and mortar stores.