You could perhaps write a feature-bare clone. Here's some basic features:

    - search (the various search pages)
    - trending
    - channels
    - subscription
    - video uploads
    - history
    - comments
    - likes
    - upload
    - video editing (most of this is in browser, but still)
    - livestream
    - video analytics
    - payment and ad management
    - video comment review and moderation
    - translation
    - captioning
    - video replication, multiscaling, caching, and resolution management based on network speed
    - video recommendation
    - cards, overlays, annotations, etc.
    - music and sound effect search
    - antispam
    - dmca and copyright tooling

And that was 5 minutes of poking around.

> resolution management based on network speed

Not so much a feature of YouTube as it is a feature of HLS/Dash... but yes, it means you've gotta transcode the source video into multiple different bitrates.

Even outside of that, I can override the bitrate in some instances. But yeah, I was mainly talking about the necessary replication, cache, and transcoding (and I actually forgot about the multiple codecs, which they also provide, in addition to multiple resolutions/bitrates)

This comment made me wonder what you consider to be a complex site.

Not a video host with comments. That's practically CRUD. A very solved problem.

Well, go on then, why spend just an afternoon when you could spend 5 whole days. Make a YouTube that's 10x better, host it from your closet and watch the megabucks roll in as you take down Google.

But, really, what site cannot be boiled down to practically CRUD? That does not help us understand what you believe is a complex site.

Is this supposed to be some kind of no true Scotsman?

See "Code: It's Trivial" https://blog.codinghorror.com/code-its-trivial/