YouTube provides RSS feeds. You could use an RSS reader to subscribe to your channels. I do, it's marvellous.

On mobile I use PipePipe for listening to stuff (like presentation videos) in the background and downloading offline audio and video.

We are oft implored, not only by our famous and much-valued dang, but also the other guy (whatever his name is. He does a great job too though), not to editorialize the titles by submitting submissions with titles other than the actual title. How can you tell if the submitted title is other than the actual title? That's easy. You read the one and read the other and compare the two and see if they're different. (Which is another way of restating the previous paragraph.) In this case: they are. (Or at least were at time of writing! Since you'll be reading this in the future.) Hence my complaint.

The vertical video thing? That was just my little joke. OF COURSE I KNOW THAT VERTICAL VIDEO MEANS PORTRAIT VIDEO. And, yes, I have visited youtube.com, and have had a big pile of portrait shorts shit up the feed, same as everybody else. I am not completely... wait, hang on. I am completely stupid. Because I thought it would be so obvious that it was a joke, that nobody would bother to quibble. They'd just chuckle at my attempt to amuse the reader, or roll their eyes at it and ignore it, and then go on to moan at me about some other part of my post. Though, reading my post again, more fool me perhaps. I guess I didn't leave people enough other material to complain about.

Sorry. I'll try to do better in future.