A lot of Internet marketers are anxious to produce an e-book as quickly and cheaply as possible so they have some fast content to share with current and targeted subscribers. An easy go-to format many of them choose to produce that e-book is the .PDF because most computers come already equipped with Microsoft Office, and they can easily convert a Word document to a .PDF with the click of a button. I'm here to say, "Whoa! Slow down!" Fast content often equates to sloppy content, and people will see right through that. It will diminish your credibility and your e-book's value in the eyes of those subscribers which defeats your whole purpose in producing one in the first place. On the thread I posted here two days ago, I briefly touched on another caution regarding simple .PDF files. I said I don't recommend trying to sell e-books in the .PDF format because they are far too easy to copy and share with others unless they are copyright protected using something called digital rights management (DRM). There is a time and a place for a .PDF in an email marketing campaign. It's the perfect file format to use as the free product you're offering to entice people to subscribe to your emails from your opt-in page. In my opinion, that's all you should use it for. Other than that, you're better off to produce either an .ePUB (the format used by KoboBooks) or a .MOBI (the format used by Kindle) for any e-book information product that you intend to sell. And never never send it to people by email. Sell it through the proper channels so that it can only be downloaded to one device at a time by the one person who has purchased it. This will protect you and your valuable information product from online piracy.
I hate the .PDF format. Unless it's a document I absolute have to read, then I will. Other than that it will be ignored.