Per Google, personalization of search results is really "very light"

What about the display ads that chase you around the web? They seem highly personalized to me.

For example, if you do a google search for web hosting, you'll likely start seeing ads for web hosting companies all over the place.

What about the display ads that chase you around the web?

Ads are not search.

I find this surprising, but then again "very light", I would have thought that is was "somewhat dark" .

Also you can flip this, what is actually being said is that language and location have a very big influence.

Well, personalization could definitely be "very light" in a big data of way, yet it can also be "very heavy" in smaller niche verticals that some of us operate in. I believe that it is more true for queries that Google isn't confident on ranking.

I don't doubt for the most commonly searched keywords, there is very little to no reason to personalize...say..."Amazon", or "Facebook".

Averages can be deceiving, IMO.

I've always had a problem with the idea of personalized search results. Rankings should be based on the overall popularity of a page across all users, not how many times the page, or other pages on the same site, appear in your personal browser history. That never made sense to me, and I'm not surprised to learn that it's not how Google works.

Even location makes little sense to me. Why limit someone's search results to sites that are closer to home? Apparently Google does actually do this, but it just seems ridiculous, especially for information-based queries where you want the best possible answer to your question. Who cares which part of the world the answer comes from?

Most people searching in the same language and same location will see largely the same things.

What does “largely” mean? People can make a living on the difference between #2 and #3.

May be Google is also trying to demonstrate that they are not invading privacy of users too much... of our day, we must play low profile on this subject...

Personalisation = Profiling

Profiling is bad in the post-Cambridge Analytica world. And see also GDPR Art 21, which requires safeguards where profiling has a substantive impact on the data subject. The merits (or otherwise) of the argument that CA / FB won the election for Trump (and apparently Brexit) mean that Big Data has to play down the role of Profiling, so it's outcomes are trivial, and therefore not subject to safeguards.

When you only have 10 slots at most, determining User Intent is a necessary part of satisfying the user. It is therefore "surprising" that Google claims that personalisation is light.

Although, of course, in comparison to Language and Location, it would be. Language and Location combined basically reduce relevant sites by 99% or more, whereas personalisation just tweaks the order a bit.

I've long felt that a lot of personalization comes in the suggestions made in Google autocomplete, which, if you look at them, you can see are influenced by your recent searches, and/or your location.

I haven't tracked these suggestions systematically for quite a while, since the tools that were available have been removed... but I think in part that they've been removed because they were for static suggestions.