system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how do books sometimes have on the cover "the new bestseller". How can it of been a bestseller at the time the cover was designed and no copies had been sold?
gpt
Because there's no formal definition of what a "bestseller" actually is or not so anybody can call anything they want a bestseller. You'd probably upset the bookstores you need to keep onside if you started calling shitty books by unknown authors bestsellers but you could.

There are lists of "bestsellers" out there but none that is official recognised as being the seminal authority (like the billboard charts used to be for music).


It's very similar to how movies will call something the "New Michael Bay Blockbuster" before it's even been released and they know what ticket sales are going to be.