一千萬個為什麽

First, a note: I will not be considering PDFs in this answer, because I do not consider PDFs to be ebooks. There are a number of reasons for this, like lack of reflowability and end-user customization options, but the primary reason is that PDFs are not generally sold at sites that sell ebooks--you can't sell your PDFs through iBooks or the Kindle store or whatnot. Others have other opinions, and that's fine—the relevant info is that I won't be considering PDFs here.

In terms of variety of devices supporting the format, epub is the clear standard—it's supported on nearly everything that reads ebooks. When you look at numbers, though, it's a different story: according to an article at Digital Book World, a recent Book Industry Study Group found the following statistics to the question "Where do you typically acquire ebooks?":

Amazon.com website: 51.3%
Amazon App: 15.7%
iBooks/iTunes (Apple): 8.2%
Barnes & Noble App: 6.1%
Barnes & Noble website: 5.7%
All other sources: 12.8%

這意味著亞馬遜占電子書銷售量的2/3左右，使得他們專有的mobi/KF8格式成為主流格式。

In essence, there is no "winner" yet, and there is not likely to be any time soon. Apple, Google, Barnes & Noble, and Kobo are enough to ensure that epub will remain alive and kicking for quite some time. With a majority of the sales, Amazon has no impetus to switch to a standard, and they don't appear to be in any danger of losing much market share. Where we are is where we're likely to be for quite a while, which means making two formats: epub and mobi/KF8. fortunately, Amazon has gotten much better at making tools that convert from epub to their format, so concentrating on epub will give you something for Amazon as well with little extra work.

Amazon has over 2.8 million ebooks, including nearly all public domain books. See the left hand column, which provides an update to date count of ebooks available: http://www.amazon.com/s/ref=lp_154606011_ex_n_1?rh=n%3A133140011&bbn=133140011&ie=UTF8&qid=1410374478

這280萬本書使像古登堡計劃這樣的統計數據顯得微不足道。

您的引用“EPUB格式是支持最多的與供應商無關的基於XML的格式”顯然旨在將MOBI/Kindle從混合中排除，因為它不是與供應商無關的。當然，在亞馬遜之外，這是主導標準。

但更重要的是，你為什麽想知道？

如果答案是因為你想知道用什麽格式來發布圖書，而你想構建一個電子閱讀器應用程序，而你正在撰寫一篇研究論文，則會有非常不同的含義。

如果您是出版商業小說的作者，那麽您可以參考，你必須在MOBI上發布才能取得成功。如果你是獨立作家，亞馬遜在獨立作家市場中的比例甚至更高（有趣的是80 +％），所以它變得更加重要。

如果您在訪問至關重要的地方提供電子書，例如必須向所有學生開放的學校教科書，那麽您必須同時在EPUB和MOBI上發布。

由於EPUB和MOBI可以很容易地來回轉換，所以有人可能會說這個問題是無關緊要的。只需提供兩種格式的圖書。