Spoiler for those too lazy to click the link: He gets fifty cents from the sale of a paperback and two bucks from the sale of a hardcover book. From a $10 paperback, he gets 50 cents, and $2 from a $25 hardcover - 5% and 8% respectively.
In short, don’t publish a book unless you expect to sell hundreds of thousands of copies, because it will take you years (the time you spend trying to get a deal) to get to a position where you’re able to owe your agent and publishing company hundreds of thousands of dollars. They pay you in loans, after all, and just hope you’ll get rich.
A compelling argument for self-publishing via the internet, though you’d have to get some damn good press. Paypal and your choice of delivery method would obviously take a cut, but even if you’re getting $4 out of the sale of a $5 eBook, you’re doing pretty good.
edit six months later: wow lol why would I link to a twitter account and expect people to be able to find the tweet I’m talking about