Viewability is an increasingly important term in the media industry. It is an advertising metric that attempts to track only impressions that readers actually see. Measuring impressions alone does not indicate that a reader scrolled down the page see a particular ad. Understandably, more and more advertisers are beginning to expect viewability metrics before they partner with a publisher. In the following Q&A Denise Colella, former CEO of Maxifier -- an ad performance optimizer for publishers and advertisers -- explains why publishers need to pay attention to this metric and how they can integrate it into their analytics.