SA was very influential, but how could Lowtax have become a billionaire from it? I'm not sure obscure Internet comedy is all that lucrative.

I was being hyperbolic about the billionaire claim. Mainly SA was ahead of its time on what the internet could be. What people were willing to pay for and what makes a good community. It failed to take any of those ideas outside the realm of a comedy forum, which isn't a bad thing, maybe Lowtax was happy with that.

I'm wistfully in what-could-have-been mode since the products I use these days (Reddit, Twitter) are a poor approximation for what SA was at its height.

I'm not so sure, plenty of people became billionaires from the trends that directly originated at SA.

Examples?

Tyler Malka (Evilore) of Neogaf (gaming forum) boasted many times about being a millionaire from ads.

tumblr was sold for $1.1 billion, and it's largely obscure Internet comedy.

Tumblr is a lot closer to a social network than a forum, and I'd say only a small subset of it is comedy. Also, Tumblr has 460 million registered accounts and SA has 200k. That's probably partly because it costs $10 to sign up on SA, so alt accounts are uncommon, whereas accounts are cost-free on Tumblr, so some people may have many alt accounts. But Tumblr still gets way more traffic.

I haven't used SA; how did it go wrong?

Signup fee for an internet forum and the occasional over-moderation kept the userbase from really exploding. On the other hand had this theoretically has kept the level of the remaining discourse high for the remaining users.

There's a joke about one of these events.

One year the SomethingAwful.com forum moderators got annoyed at the annoying anime fans, so they banished them. 4chan was born, yadda yadda, Donald Trump is elected president.

So...it didn't go wrong? Why should the ultimate goal of a forum be growth?

And, I don't think you can blame SA for 4chan, nor 4chan for trump. Both trump and 4chan meet a demand, and that demand would have been filled, one way or another.

Chris Poole (Moot) founded 4chan after being banned from SA (in the version I heard it was on accusations of pedophilia, because anyone who finds anime characters attractive is clearly a pedophile). SA was far more influential in creating and shaping 4chan than anything else, even the Japanese forums it was imitating (2chan, etc.)

Would there still be something that fits roughly the same niche as 4chan, if 4chan didn't exist? Most likely yes. But it wouldn't be anything like the 4chan we know today.

The SA moderators are extremely touchy about pedophilia and will permaban with basically just an anonymous accusation and maybe some fabricated "evidence". They also don't respond to appeals.