OnBuy.com, a U.K. online marketplace similar to Shopify, searched Instagram and determined that the book cover most often appearing on the social media site was Harper Lee's To Kill a Mockingbird, with 181,000 posts. This was followed by Heir of Fire by Sarah J. Maas with 154,000. The Harry Potter series was the most instagrammed book series overall. OnBuy, which sells books on its site, determined that the most common colors used in the top instagrammed covers were red and black.
The site also surveyed 2,201 people and 44% said they have chosen to buy a book just because of its cover.