My thinking was that Reddit has always been a "news" site, and the majority of what active, ad-consuming users are looking at is likely to be content added in the last few days. It feels like this is only becoming more true as time goes on; modern social networks seem to actively discourage looking through the archives. I could be missing something, like AI training as someone else pointed out.

I agree the majority of the value is in the current activity but theres definitely some in the historical data, both for AI training (as you mentioned) and for people looking for information on topics that have been discussed in the past.

My assumption though is Reddit has already done the math regarding the threat of reduced value as a knowledge repository from people deleting comments/posts and decided the value they lose from pissing people off is smaller than what they gain from the changes that everyone is angry about.

Especially because they probably keep backups they can pull from and (as people have pointed out) historical post/comment data is already archived and available all over the internet. Legally that data is still the property of Reddit so if AI companies want to use it without breaking laws they'll need to pay them for it.

> if enough users suddenly remove their whole history from Reddit.

Reddit has around 52 million users according to this unknown source I dug up[1]. Only the people who care the most about this situation will actually delete their posts (especially with a python script). What's that, like 500k people? So yeah only the "best" data will be removed from Reddit, but that's not even the data that makes them money. It's your data, remove it, but I think it's an illusion that it'll hurt Reddit any.

[1] https://backlinko.com/reddit-users#reddit-daily-active-users

overwhelming majority of their users are readers. very few actually bother to write something, and even fewer have something valuable to say. those are the ones with high karma and those are the ones that drive traffic to the site. so yeah, even if 50k users who drive traffic delete and move out, it matters to the site.