We have our own DRM system that has secured the content delivered via our Ebook Reader apps since 2007. It is not based on Adobe ACS. Having our own DRM system improves usability for our customers, and enables us to respond quickly to new requirements and trends.
Uhm… if you want the solution to be as flexible and as usable for your customers as possible, going with a custom DRM sounds like a weird approach to say the least. Things got even stranger when I checked their FAQ:
Rather than implement our own bespoke DRM we instead use Adobe DRM. This is the industry standard and ensures that if you buy a DRM protected ebook from eBooks.com it will be compatible with the largest number of devices and software. If you are concerned about whether your device is supported please see our device guide.
If only they could make up their mind on what DRM strategy they’re having. That being said, they are at least quite transparent regarding who determines whether a book they sell is DRM-locked (whatever system they are using) or not:
Are all of the ebooks that eBooks.com sells DRM protected?
No, but the majority are. It is the publisher’s decision whether DRM is applied or not. And it can vary from ebook to ebook, and even from format to format for the same ebook.