system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Why is there a waiting list for digital book downloads?

My mom was wondering.  She doesn't understand why, if a book is a digital download, would there be a waiting list to borrow it from the library?  I don't get it either.  Thanks Reddit!
gpt
Publishing companies don't like the idea of anyone being able to read their books anytime for free. So when they let libraries use their ebooks, they make the library put a limit on how many people can use it at once.