RSS and Atom are increasingly important technologies that enable users to have efficient access to emerging online information. There are now several million active information feeds (estimates vary) that use RSS and Atom. Many of those feeds, perhaps the large majority, are created automatically by tools used to create weblogs. Such feeds contain information on topics as diverse as XML, individual software products, cats, Microsoft, the Semantic Web, business information, and pop music. Millions of users across the globe are increasingly using aggregators, software that allows subscribing to information feeds and display of new information as a more efficient way to remain up to date on subjects of interest than the former approach of manually browsing multiple Web sites. Businesses increasingly use information feeds to keep up to date on their markets, the activities of their competitors, and so on.

RSS and Atom information feeds have moved from being the plaything of a few to becoming an essential business tool. Understanding the detail of information feed formats and how to manipulate information feeds will be foundational to many upcoming pieces of software. This book aims to equip you with the understanding and skills to understand information feed formats and to use RSS and Atom feeds effectively in the software you write.