"The internet" has decided that vertical video is "wrong" or "broken" and want the phone manufacturers to "fix" it. YouTube enforces it by only showing a horizontal aspect ratio, even if you select "full screen" on a smartphone held in portrait mode. Facebook gets this right, and I've seen comments saying G+ does also. (Maybe they haven't gotten around to "fixing" that player yet.)

So WTF? If I take portrait photos, nobody bitches. If my subject is inherently vertical, what's wrong with shooting vertical video? It'll be pillar-boxed on a big screen TV? Boo-fucking-hoo. It's still big as shit. But force it into a horizontal format then letter-box and pillar-box on my damn 4-inch phone display? Fuck you sideways.