There is no need to pronounce that the media buying landscape has changed. Within an article by Search Engine Watch this shift is described by mooving towards paid media with the consequence of the need of new skills. And indeed, formerly there have been search engine ads and display, which was disseminated over some well known portal. Especially the latter has changed by the adoption of realtime and programmatic buying. So media professionals today need additional knowledge about bidding processes.
The same is due to social media ads appearing on Facebook and Twitter and other large or niche social networks. All these networks have specialities making the media buying process a more challenging task. At all today we have a landscape of a broader media mix: Paid Media Is the Future.