As Ron and Ian have already said so eloquently, and others have expressed less eloquently, it all has its place in the equation. Including rankings. The trick is in getting the right mix so that the information becomes more useful and doesn't distract one from the important stuff.
Nueromancer: The key to the How many people are using Personalization is a tricky one. Previously people would only get personalized results when they were logged into their account at a search engine. This is changing with the push towards Universal Search, Geo-localization and Automatic Personalization. The idea being that if the search engines can track what you've done before whether you're logged in or not (and they've always been able to but are just starting to use the info) they can then offer you personalized results, ones that hopefully better match what you're looking for.
Is this happening already? Yes it is, on Google at least. It's something I've actually noticed over the last few weeks from using Chrome and searching on Google. It was something that was relatively easy for me to spot. The reason being that a few weeks ago I was doing some personal research specifically on sites based in the UK. Since then, even if I'm conducting a more general search and doing it on the .com version of Google, I notice I'm getting a lot more co.uk results show up than is the norm. Even though my IP number is obviously US-based and the things I'm searching for are available in the US.
I'm not logged into my Google account when conducting these searches. I suspect they're probably using a cookie, because if I change to a different browser (say IE or Firefox) I get more "normal" results. So for me at least they're already tinkering with the idea of Automatic Personalization, regardless of whether I'm logged in or not.
Quite frankly it's not working all that well in my case, probably because they don't yet have enough data to make intelligent choices. The moral being that just because I'm interested for a few days in looking up Bed and Breakfast places and tourist type things in the UK and throughout Europe for a little trip I'm planning, it doesn't follow that I want to pay International Shipping rates to purchase a paper folding machine or shrink wrap machine that would have to be shipped from the UK when I can buy 'em 30 miles down the road from me and pay for local shipping.
I've considered zapping my Google.com cookies in Chrome so that it'll act normal again. But I've decided to leave it for the moment so I can see what's happening on the Automatic Personalization front, then do my normal searching in another browser.











