I thought YT counted multiple viewings from the same person as a single view. Or it would be too easy to game. I at least imagine there would be a time cutoff before it considered counting a new view from the same person.

There are videos with billions of views, I doubt that much fraction of the planet saw them.

I imagine it would horrible performance-wise. You would need to store list of browser fingerprints and check it on every view.

I think youtube does a bit of checking on views. The view counter is not real, IIRC the delay is due to asynchronous processing, youtube has time to do stuff in some cases. That's why a lot of videos are stuck at 320 views, that's the supposed limit above which the counting goes async and you get lots of vid with false views.

No, if a single person watches more than once it is counted as multiple views. For the video creator, you can see a metric called "Unique Viewers" and see your "Average Views per Viewer" number which helps you see if people are watching multiple times.

All that being said, I do think there is some detention of fake views, especially if they come from the uploader themselves.