I don't know why I decided to browse a popular sub today, r/books (logged out, I don't have an account anymore). Maybe I hoped I might learn something. As if! People make the absolute same posts over and over. Today I read a book! I read one page of Harry Potter and the Philosopher's Stone and I already know it's a masterpiece and the best book ever. I read 1984 and wow, just wow. I hate stickers in book covers. Audiobooks good. Actually audiobooks bad. I hate movie covers. The absolute same thing as yesterday, 6 months, 1 year, 2 years ago. May I remember this feeling next time I decide to browse Reddit again.
Why do old users put up with this? How can they even pretend that they haven't already read this stuff a million times before? Or are these subs 100% driven by new users and repost bots? The complete lack of new content is mind boggling.
It doesn't really explain why people are posting the same thing today as last week. Everyone who is posting today was alive and able to read books last week, and the vast majority was already a Reddit user. We would have to assume that nobody who posts on r/books subscribes to the sub and reads the posts ... which I wonder if it's a real possibility.
You might be right. I myself have never really thought of sharing my impressions of the books I read, so can't really say what kinds of behaviour can be expected on such a sub.