Theoretically:

Let's say there are seven people: Happy, Dopey, Grumpy, Sneezy, Bashful, Sleepy and Doc. Let's say all seven of them, follow #atheism.

You follow Doc and Grumpy, Doc because he's a thoughtful and measured orator and Grumpy because he's entertainingly cantankerous. Dopey you don't really care about, Sleepy and Bashful rarely say anything of interest to you and Happy, other than the fact that he's constantly seeking affirmation for his beliefs, doesn't bother you enough to ignore.

Sneezy, though. Man. Sneezy is like a disease all over your feed. Bile and mucous about Christians, nothing but Courage Wolf advice animals, gets up in your grille whenever you suggest that saying "gesundheit" is custom rather than proselytizing. So you ignore Sneezy.

Of the six people who make up your #atheism feed two of them entertain you, three of them you could care less and one of them is borderline. So after a few weeks you give up on Happy.

Then a miracle occurs! Happy posts something interesting! It provokes a lot of comments but you don't see it because it isn't in your feed! What do do?

Click "chatter" to the left. Behold. You can see what Grumpy and Doc are talking about - and what they're talking about is a post you wouldn't have seen otherwise.

In other words, you've got two different dimensions of follow: You can directly follow Doc, you can directly follow #atheism. But you can also follow #atheism (less the crap that annoys you). This allows you to do a little "interest algebra" - almost a "social media Laplace transform." Your true feed, should you click on "chatter", is "[(#atheism -Happy -Sneezy)(#Doc)(#Grumpy)]". The only way you will ever truly miss anything Happy and Sneezy say is if neither you, nor Doc, nor Grumpy find it worthy of comment.

That dusts the shit out of Subreddits.