Do not adjust your computer screens. There's no problem with YouTube, other than the fact that it's getting a little misty-eyed -- by choosing to celebrate the 57th anniversary of the VCR with a little added analogue character on its digital videos.
On plenty of YouTube videos you can currently find a small VCR button: click it, and the video you're watching will start to display some of those wonderful (awful?) characteristics that your old cassette player used to provide.
It's a quirky way of celebrating the Ampex VRX-1000 -- commonly considered the world's first practical videotape recorder when it was launched on April 14, 1956, at the National Association of Radio and Television Broadcasters Convention. The device made a lasting impression on home entertainment, but thank goodness things have moved on. [YouTube]