In the last 10 year circa, the Related Videos on Youtube were composed by two large group:
If you are watching someone painting, you get suggested other painters.
Often are related content from the same source author.
Based on your past activities, if you are watching a painter you might even like other visual arts
And so, a few unrelated recommendation show up because you behave similarly to other anonymous stranger. Despite the total asymmetric of decisional power of YouTube, at lease these video were explicitly marked with a label: Recommanded for you. That was a small form of transparency on that attention stealing machine that Google bought.
The percent% is computed by confronting the total amount of related video and the explicitly Recommended for you, as they were served to our (too small? then join us!) group of 185 partecipants.
We document the data minimization, the code is free software, and we care to explain the (open and replicable) research methodology! We believe anyone might want to audit the Youtube algorithm. After all, if Google experiments with you, why you shouldn’t experiment with them?
Recommended for you was a small information that display, somehow, the interest of Google in being explicit on what was algorithmically selected for you compared to what is (algorithmically, again) selected because content related. Well: not anymore, it’s gone!
This might not be a surprise if you were using the browser extension, because the stats display gradually changed from left to right:
(The details also report the amount of live video present in the recommendation. This is not relevant for this blogpost.)
Please consider this project, despite unique in its model of data collection, sharing, and potential reuse by you like anybody else, is currently unfunded and maintain with not small difficulties.
A thread from Reddit, September 2020: Is it me or has youtube recommended system gotten way less "explorative"?.