We are living, aren't we, in a world filled with informations, informations structured in and expressed via blog posts, news, printed papers, books, etc, grouped knowledge that helps us improving a language, learn about the history of past generations, create foundations for to-be-pursued directions, etc.
EPUB is a widely used and appreciated e-book standard, presenting itself as a reliable supported-on-multiple-devices-and-OSes file format, thus the user is able to consume EPUBs on computers, smartphones, tablets, etc.