I'm on the opposite end of the spectrum, I guess. I've unsubscribed everything, hidden/removed all recommendations and like/dislike, view count, subscriber count, etc with some user CSS/JS. Logged out for good measure.
Then I've put the 20ish channels I care about into my RSS reader (NetNewsWire + The Old Reader, I recommend both), which allows me to do things like "mark all as read" on whole folders.
I only had to do this once, so I've thrown away the code, but I had two bits of JS: to generate an OPML file with the feeds for import, and to mass-unsubscribe everything afterwards. Maybe I should rewrite and publish that somewhere? If there's interest.
Then I've put the 20ish channels I care about into my RSS reader (NetNewsWire + The Old Reader, I recommend both), which allows me to do things like "mark all as read" on whole folders.
You can get the feed for a user/channel like this: https://www.youtube.com/feeds/videos.xml?user=xxx or https://www.youtube.com/feeds/videos.xml?channel_id=xxx - it's a bit cumbersome since YT doesn't provide either link in the channel's meta tags.
I only had to do this once, so I've thrown away the code, but I had two bits of JS: to generate an OPML file with the feeds for import, and to mass-unsubscribe everything afterwards. Maybe I should rewrite and publish that somewhere? If there's interest.