[will4274]

It does actually. You can exclude subs from /r/all.

[maxerickson]

There is also the excellent setting "don't show me submissions after I've downvoted them".

Click once to mark something as the sort of thing you don't want to see and to hide it!

[nailer]

Not according to /r/help:

https://www.reddit.com/r/help/comments/44498b/how_to_hide_or...

> there is no basic Reddit feature which will hide or filter a subreddit from the /r/All page.

[nsuser3]

Well, the help is wrong then: http://i.imgur.com/YIEduLP.png

[TJSomething]

That page is out of date. They added filtering for everyone in November.