Speaking as someone who worked for another big web search engine in the past (not G, not B)
And counting good/bad clicks for a given (query, url) pair is just the tip of the iceberg. There's a lot of other interesting stuff you can do with them _if_ you have the data. Deep learning/NLP with clicks as training signal is probably the most exciting area to me, to name one. Unfortunately almost all of the data currently gets nabbed by google, other search engines are just getting by with the scraps. And it's very hard to bootstrap a competitor from scratch - for example Cliqz had to resort to some shady deals with Mozilla just to get any data to start with.
Sorry, appeal to authority is no argument. Direct experience is valuable if there's an argument or some real scenario we can dissect, otherwise it's nothing more than a baseless claim. Without concrete examples, it's not even an anecdote. And there are plenty of anecdotes about search results for in-depth content becoming harder and harder to find.
The person I was responding to posted that they're using this training data to order the top 10 results or so. That's already an indication that it's not very helpful for me. I don't get frustrated if the top few results are in suboptimal order, I get frustrated when I get pages and pages of garbage and irrelevant results and can't seem to get anything useful out of it.
The gaming part is where there's a lot of importance, since it forces the machine to learn which users are acting nefariously.
Specifically they also measure metrics like "regret" - if you went back to the search results and chose something else this indicates it wasn't a useful search result for the query and this counts against it.
In theory this is quite a nice defense against clickbaity, content free results.
I explicitly addressed this:
> clicking on many results can indicate that they're bad (I click another result because the previous wasn't good), or because they're good (I'm browsing choices).
You don't know the reason why I clicked back. Maybe I got what I needed at a glance, and I'm browsing to the next thing to see if there's more of what I need.
You don't know that the Average Joe (and a million other Average Joes) wasted 15 minutes on clickbaity content free crap despite not getting anything useful out of it. You know, those same SEO spam sites are trying to find ways to make the user stay as long as possible; they are in the game. And I'm sure there are plenty of gullible users who will stay. Who knows, maybe SEO spam is working and that's precisely why we see SEO spam sites in results?
Again, I think training like this is pretending the problem is much simpler than it is. And I think that there is a real danger that training like this just optimizes for 1) average users 2) sites that managed to game the system with their SEO. Neither is optimizing for quality results.
That theory has so many holes and pitfalls.
Maybe the best bet is for a search engine to try to include a simple, non-intrusive method of getting user input to determine the usefulness of a search result. Like, if it determines you came back as a "regret", maybe a ThumbsUp/ThumbsDown icon next to the last link you clicked to get you to say whether that link was useful in any way, or maybe a "block" option as well to say that you never want sites like that again.
I should, then, expect dramatically different results when I use someone else's PC or a public computer. I have not witnessed dramatic differences.
We may not know exactly why you clicked back, or why Joe wasted 15 minutes on a site, but from all clicks in aggregate and from the human-labelled data, we can tell how that correlates with the clicked site's relevancy and quality and utilize your clicks accordingly to improve the ranking.
Finding such correlations is still by far and large what all search engines do, rather than trying to truly understand the query. It's only now starting to change with recent advances in deep learning and NLP.
A million flies are attracted to shit. I don't believe this sort of training data will ever become useful if it's in the same pool with the rest of the world. See also: voting with your wallet against the tyranny of the majority of uninformed consumers who buy whatever is most marketed. Those pennies don't matter.
In fact, I believe this sort of training and optimization for the mainstream plays a role in allowing bad results to proliferate.
This is before we even consider the fact that clicking on many results can indicate that they're bad (I click another result because the previous wasn't good), or because they're good (I'm browsing choices). Dwelling long can be bad (crappy & slow site, it takes me long to find the information I want or turn away) or it can be good (I found good stuff and I'm spending a while on it). Whatever conclusion your training system draws might be completely wrong. And probably prone to being gamed.