DRM always restricts the paying customer. With DVDs they got the unskippable piracy warnings, while people who downloaded the ripped version wouldn't see it ...

The hope publishers have is that it slows distribution a bit and they use it as attempt to manipulate people to allow stronger punishment of infringers.

What are you talking about? Ebooks are tiny. It's just text.

Mass sharing a scanned book, particularly one that was not OCRed, indeed usually takes too much work. EBooks, or rather most of them, are tiny epub files with little to no images, 5mb maximum. There are sources distributing ebooks at scale, libgen.io is a prime example, the ebooks channel on IRC highway and myanonamouse, a private ebook and audiobook torrent tracker that some people apparently use also exist. There are rumours of private collections spanning millions of titles that fit on a single, albeit large, hard drive.

There will always be hacking. When you sell ebooks without drm and with just reasonable watermarking, you remove all the incentive for ethical hacking. This remains only the unethical hacking (the thieves).

Maybe they should be.

> Something does not compute here.

That's right. They are trivially copyable, but the copies are easily traceable. Compute now?

These aren't visual watermarks like what you'd get on physical paper. They just alter the digital copy so that it can be traced back to the buyer, and people are deterred from sharing it on the web. It's a very elegant solution if the 'watermark' can be made hard enough to remove, and I can see quite a few workable approaches.

It's not that kind of watermark. Rather, usually at the beginning, there'll be some text saying who bought the book, along with some kind of identifier. The id can also be hidden inside the file.

These watermarks only appear a few times in places like beside the page number. You'll have to provide a darn good explanation to convince me it makes the book harder to read.

And yes, it's still trivially copyable, but that makes it better in any way than DRM: it can be traced back to the original owner but doesn't make it unnecessarily hard to read it on multiple devices.