"According to several app makers and media companies, many of the world’s video consumers don’t seem to think vertical videos are wrong — in fact, a lot of us prefer them."

"There is a simple explanation for the dawning preference. According to the venture capitalist Mary Meeker, we now collectively spend about 30 percent of our screen time with devices that are best held vertically, like smartphones and tablets. That time spent is growing quickly, and on tall screens, vertical videos simply look and work better than those shot 'correctly.'... If you peruse some of YouTube’s vertical videos on your phone — say, a video of an inflatable Minion rolling down a street in Dublin, or of a man with a spinal cord injury taking a few halting steps after being fitted with a mechanical exoskeleton — the argument that vertical videos are unsuited for showcasing most events falls apart."

From "Vertical Video on the Small Screen? Not a Crime."