@patrickstewart @bookstodon My knee-jerk reaction was to vote for purchasing on the author's site because I'm assuming that's a better way to support authors... but on second thought, it's so much more convenient to use a digital retailer that, if I'm being honest, that might be my preference. Like, if I had to enter payment info on a different author's site every time I buy a book, I probably wouldn't bother for any but my few favorite books. Plus it's easier to discover new books using a consolidated site such as a digital retailer or marketplace.
Perhaps the ideal situation is a marketplace where authors can list their own books, leaving it to the marketplace to handle payments and promotion of related books. But it'd be critical that the marketplace takes only a reasonably small fee and passes on most of the money directly to the author.