It seems we are confused here, or maybe the question was misunderstood.
I probably misunderstood the question.
Indeed such a question has multiple answers depending on the context.
The main "rule" here is that there is no cross compatibility between DRM formats, and all companies try to lock you in a closed proprietary system (like Apple does egregiously).
There are different "actors" to consider:
- The device itself (e.g. Kindle or IPad)
- The reader, the software that allows you to read eBooks (e.g. Kindle Reader, or FBReader, or iPad eBook reader, etc.)
- The eBook store (now getting decoupled from the reader software)
- The DRM system
- Repository: often in the cloud, where all the eBooks you bought reside (and can then synch down to your device)
It's easy to confuse terms and roles (I write it more for people with less insight in these systems).
the Kindle is Amazon-exclusive, right?
Pretty much yes, the system allows only eBooks bought from the Kindle Store.
No additional reader can be installed, and only one eBook shop is allowed.
However on Kindle you can still read your own "documents": in this case it means both your own pdf/doc but also any DRM-free eBook.
Things change a little with Kindle Fire because it's based on Android, so it will be possible to install 3rd party readers (however only the Kindle Store will be allowed)
The same as it happens on iPad where you can install multiple readers, connecting to multiple repositories, but only one store is allowed.
Say hypothetically you bought a book through company A's proprietary ebook device, and then you switched over to company B's system. Company B also produces a Kindle-like device for reading Company B's ebooks. Do you retain your old reader for Company A?
If the device of company B is as closed as the Kindle, then yes.
If the new device is based on a more open system (.e.g Android based) then you just need install the reader software for company A.
Many of us don't accept it gladly, but are forced to because we aren't offered any other choice. And a few don't at all.
True.
I admit I hate these closed systems... I opted into Amazon-Kindle only because i really loved the device itself and the excellent experience of reading books on it (traveling a lot for work a kindle type of device helps a lot).
Thanks to my work I also have the opportunity to try out and use personally all those devices for free: that makes a huge difference!
(I do pay for content that I may buy on them).
Seems to contradict what was posted above.
I was trying to find quantitative data about the effect of eBooks on general books sales.
I did not find some definitive answer concentrated in one uber-article.
However I found many pieces of information.
My take is that sales of paper books, especially hard covers, are in very fast decline.
The decline started when the eBooks didn't even exist, and now is getting worst and worst.
Sales of paperbacks were declining too, independently from eBooks.
If we exclude hard covers from the equation it seems to me that sales of books (paper+ebooks) are essentially flat: no sharp decline nor sharp rise.
It seems that sales eBooks cover what is lost in sales of paper books with some positive margin: we could have hope that with time the total market will grow.
What is decreasing is the average revenue per sold book (revenue, not profit).
and naturally eBooks are killing traditional bookshops.
Agreed. I want to buy a full copy that I may use at my discretion. That's how we used to do it, and that's how I want to conduct business.
I fully agree here.
The world, however, is going in a different direction.
Unfortunately too few people (consumers) are aware of the problem and very few actually complain.
See the many threads on this forum about Steam and CivV to get an idea how many people do not consider this lock-in as an issue.
I think backwards-compatibility is accurate to describe the state of ebooks right now, but cross-compatibility isn't. At least if I understand the others posters correctly.
Almost all systems care for backward compatibility (at the end master versions of the eBooks reside on the companies servers).
What is strongly opposed is cross-compatibility.