Both explicit (thumbs up/down) and implicit (click-aways / closing window) may count toward quality.

There are other confusing cases. I watch a lot of long-form videos, some too long to view in a single session, many of which I download for offline viewing (yt-download). I've been quite actively dissuaded from either publicly rating videos, or even linking to YouTube itself on my primary social channel (G+) given the Anschluss forced-marriage between YouTube, G+, and what had once been individual and separate accounts (similar logic applies to Google Play, and I've taken to "registering" my Android devices under randomly generated usernames).

For videos I particularly like, I may reference them, but only specific portions which I skip to, view, and then close. That's far less than a 100% view, but still significant.

It's not that I'm opposed to providing appropriateness and quality data to YouTube. I absolutely give massive shits about who they share that data with, and how. The "make it all public" default is utterly fucked in the head.

I think Google are starting to realise that.

> A better way to filter those out algorithmically would be to simply look at the thumbs-up vs thumbs-down ratio.

> The ones with misleading titles/thumbnails often have far more down-votes than up-votes

Especially once the total votes pass a certain threshold. Below a certain threshold, any activity makes something interesting; you wouldn't want to let a handful of downvotes bury something early on (as in, 4 upvotes and 6 downvotes). But once you hit the hundreds or thousands of votes, the ratio should take over.