I’m not sure if there’s data comparing spam levels from the past to now, but it’s clear there’s been a big improvement.
A bit difficult to compare that, isn't it? The only way I can think of would be to compare the length of the posts, but a short post is not a synonym of bad quality either. Or I don't know if with AI today you could compare today's posts with those of 2017 for example in terms of correctness in the use of English.