Welcome to the Metadata Millennium: A Complete Overview of What Metadata Can Do for Publishers
Although metadata has been around since well before the NSA was outed for collecting information about our phone calls, the extent to which the word "metadata" is bandied about in blogs and tweets these days is an indication of just how mainstream it has become. I bet I don't even need to define it for you. But I will. In the context of publishing, the easiest way to think of metadata is this: it's not the content, it's information about the content.