The digital advertising marketplace has become increasingly complex and fragmented, particularly as digital advertising networks and exchanges, real-time bidding and other programmatic-buying channels that allow advertisers to buy audience at scale play a more significant role. Competition from a wide variety of digital media and services and a significant increase in inventory in the digital marketplace have affected, and we expect will continue to affect, our ability to attract and retain advertisers and to maintain or increase our advertising rates. In addition, advances in technology have led to an increasing popularity in the distribution of news and other content through mobile phones, tablets and other mobile devices, reshaping consumer behavior and expectations for consuming news and information. The digital advertising model is still evolving to address these rapid technological changes. Furthermore, as the advertising environment remains challenged, media companies have increasingly re-evaluated business models that have been largely dependent on advertising, with increasing numbers shifting their focus toward various forms of digital subscription models.
https://blog.rememberlenny.com/2014/12/02/the-digital-advertising-marketplace-has-become/