EPUB, an XML format for reflowable text made from three open standards, is on its way to becoming an e-book industry standard. The standard, developed by the International Digital Publishing Forum (IDPF), is gaining support from publishers and technology firms, including Adobe, Sony, and Google. IDPF executive director Michael Smith says that five e-book formats are used in North America, but the United Kingdom, Germany, and France have all taken an EPUB-only approach. EPUB became a standard in September 2007, and the Association of American Publishers issued an open letter to IDPF announcing their support for EPUB in May 2008. Because EPUB is XML-based, it can be converted into other proprietary formats, enabling publishers to create a single EPUB file that distributors can convert, lowering costs and allowing publishers to introduce more titles to the market. EPUB is best suited for text-based materials, and does not lend itself well to documents that rely on a fixed design with heavy graphics.
From “EPUB: The Next PDF?” Computerworld Canada (07/21/09) by Jennifer Kavur