The digital revolution triggers new words all the time. Usually, the new digital inspired words arise from the need to describe a new noun or verb in the digital landscape or to label a digital version of a long established item in the analog world. The electronic book is a current example of a digital item seeking a new name. Most people verbally refer to them as ebooks, but, when written out, I have seen three predominant forms: e-book, eBook, and ebook.
The hyphenated form e-book is a logical approach. The "e" emphasized by its segregation with the hyphen makes it clear to the reader that the defining element of this book is the "e" that stands for electronic. Although a reasonable way to write e-book, I do not like it. Hyphens are always cumbersome to type. Sometimes I hit the = instead and have to start over. I remember in the 1990s when email became a well known word. I often saw it as e-mail back then, but the hyphenated version quickly was dropped by the masses who no doubt decided that typing hyphens all the time added work instead of meaning. The form e-mail is very rare now, if used at all.
The next form eBook is the one I dislike the most. Since when do we capitalize the second letter of a word? I suspect that Apple inspired this form of the word with its style of naming its products with a lower case first letter followed by an upper case second letter: iPod, iPad, iPhone, iBook. Other companies do this with various products and services too in an attempt to add distinctiveness. I suppose that's OK for the branding schemes of a company, but should this style really be applied to a basic noun? What would be the special reason for it? I know that the English language is often criticized for not making sense, but the capitalization of interior word letters has never been among its confusing habits before, and I doubt it is an element that would be beneficial to adopt. What if you need to start a sentence with the form eBook? Do you type EBook? Do you always use the form eBook even at the start of a sentence? Will we just start dropping the capitalization of sentences and make all text look like the lazy musings of a semi-literate text messenger? oBviously I vote "nO" on eBook.
The form that I prefer is ebook. It is easy to type. It has contains no random and nonsensical capitalizations. It communicates the meaning, which is a book in electronic form. I believe that ebook is the ultimate usage that will become the standard, just as email became the standard form of that word. Ebook provides the path of least resistance while effectively communicating its meaning.
Language is a matter of shared opinion. Opinions vary but usages tend to emerge as varying opinions are gradually eliminated. Language changes too over time. Maybe ebook will disappear entirely and people will call it something else and restart the confusion and creativity until people collectively narrow down the nonsense to a new accepted usage. When making a new word, people appear to fumble through various usages before settling on forms that convey meaning but don't require too much work to say or write.