YouTube is a video sharing website where users can upload and watch videos. It is one of the most popular websites on the internet, with millions of users worldwide.

Here are some Chrome extensions that can enhance your YouTube experience:

1. AdBlock for YouTube – blocks ads on YouTube videos
2. Magic Actions for YouTube – adds various features like auto HD, cinema mode, and more
3. Turn Off the Lights – dims the background of videos for a better viewing experience

As for Tampermonkey scripts, some popular ones for YouTube include:

1. YouTube Center – adds a variety of features like custom video player sizes and fullscreen button
2. Enhancer for YouTube – adds download and thumbnail options, as well as the ability to disable ads

The newest functions of YouTube include:

1. Dark mode – a new theme that changes the background to black for easier viewing in low light settings
2. Autoplay on Home – automatically plays recommended videos on the home page
3. Explore – a feature that allows users to discover new channels and topics based on their interests