Ebook File Type – PDF vs Custom
I have been asked a few times on the recommended format for ebooks.
There are a few alternatives for file types when it comes to ebooks. The most popular and best one to use if Adobe PDF. It is widely accepted in terms of that most of the people have Adobe Acrobar Reader installed on their computer which is used to open the PDF ebook.
The alternative to PDF is DOC and a few custom formats, that require custom programs in order to open the ebook. With regards to Doc format, its simply not acceptable as the ebook is easily editable in MS Word format and you want to avoid people from editing your ebook.
So, the verdict is that PDF file is the best one to use for ebooks.

Regular .pdfs or encrypted .pdfs? What level of encryption is needed for an author to feel secure that they are not going to have their hard work spread across the internet if it becomes a best seller?
Thanks!
We just use normal PDFs as with all the security it makes it hard to manage once people have problems. Just make sure to watermark the pages.
The sad reality is that if someone really wants to steal your information, they will.