Hm, that's not how correlation and causation works. For instance, the cause might be an influx of users in from all, which could be attributed to good content, that just happens to be missing. The charts seem to suggest otherwise, but data is finnicky like that. Another cause could be that the subreddit had a falling out. When he says correlation != causation, he's implying taking a logical stance that you can't just look at every correlation and assume its the cause. To see it so vehemently downvoted makes it clear that people here aren't fans of logic. It doesn't devalue the correlation at all, merely suggests the correlation be seen as a correlation with the understanding that many factors could have caused it.