system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5: How is it so many books say 'New York Times Bestseller'? How is this possible?
gpt
The NYTimes Bestseller list just tracks sales numbers - it says nothing about the quality of the book. It also says nothing qualifying about the title itself - if your book showed up at the bottom of one of the multiple Bestseller lists for just one week, you can call your book a New York Times Bestseller for the rest of its printing lifetime. There exist firms that will manipulate the list for a fee to get you onto it for that week. 

Not only that, but some authors/publishers will carry that title over to other books. If you look at some books that claim they were a NYTimes Bestseller, you'll sometimes notice underneath the header, "author" written in smaller font. This book that you are holding wasn't a Bestseller, but the author did write one in the past and can continue to advertise his work forever afterwards.