> J.K. Rowling is actually better that Hemingway
> > based
From here it spread to other communities (largely non-mainstream political communities on both the left and right). Its strongest assiociation is still with 4chan (and by extension the alt-right) though.
Edit: I just noticed this is Luke Smith's project. He's an esoteric fascist with an embarrassing love of 4chan memes. So yeah, that's where it comes from.
But usage seems to be broader according to what you wrote. I reckon the most common usage will be, that something is based, when it is unpopular or contentious, but you happen to agree with it.
I agree with that, but regard it as an evolution from my other answer meaning "established." The reference to contentious or unpopular comes because a based person has earned the ability to present unpopular ideas without repercussion.
Now when I see the term used online it's mostly in the imageboard sense of some idea or concept being 'correct' or 'agreeable' rather than the person who originates it. I think the term is undergoing a certain amount of semantic broadening too - more and more often I see it simply as a synonym for 'cool' rather than in the narrower meaning of 'this is controversial but I agree with it'.
(slang, of a person) Not caring what others think about one's personality, style, or behavior; focused on maintaining individuality.
(Internet slang, 4chan) Praiseworthy and admirable, often through exhibiting independence and security.[0]: I think the original term comes from street slang and has something to do with freebase cocaine and evolved from there through various online communities.
Is it a pre-existing phrase with its own meaning, or it's just the name of the site?
Is this a meme meaning of the word "based" that I am too old to be aware of?