Firstly, it appears that Google DOES do “personalized search” IF you have the toolbar installed, and IF you are are logged in.

For example, see here http://googlesystem.blogspot.com/2007/04/how-to-disable-google-personalized.html
and
http://www.rimmkaufman.com/rkgblog/2007/06/10/personalized-search/

I have not been able to detect any difference in SERPs so far, but I have not done serious testing.

Google “web history” is explained here
http://googlesystem.blogspot.com/2007/04/google-web-history.html

It looks like you have to specifically enable it, and be logged in for it to take effect. The above link shows how.

OT, the “disabling PWS” article above lists PWS=0 as the appropriate parameter .. here is a list of other URL parameters
http://www.joostdevalk.nl/wp-content/uploads/2007/07/google-url-parameters.pdf

The link you sent “Proof Google is Using Behavioral Data in Rankings” is long and worth reading and does report an experiment by Visio, which may or may not be conclusive. The article really goes to the issue of what else, apart from content, google is using to calculate ranks/deliver SERPs : it is not specifically pertinent to the issue of whether or not google delivers different SERPs to different browsers/searchers.

There is a consensus, of sorts, on “Important Search Engine Ranking Factors” here http://www.seomoz.org/article/search-ranking-factors
and an interesting article
http://www.seomoz.org/blog/throwing-out-the-book-on-seo
“Throwing Out the Book on SEO!”
which argues that “visitor actions” (ie on site behaviours) are the coming thing.

http://www.seomoz.org/blog/proof-google-is-using-behavioral-data-in-rankings

http://www.seomoz.org/rank-checker

You simply put your website url, the keyword you’re interested in and the search engine. It will then inform you on the position on the SERP.

I was really talking about the POSITION on the results page .. I wonder if there is a term for that.?

“Normally, if you search on different computers, with different cache, you should obtain exactly the same SERP (maybe I misunderstood you).” ..

you may be right.. perhaps it is the influence of the cache

If I search for “keyphrase extraction” (with quotes) with Google I get my article (”the Start of the Art in Keyphrase Extraction”) at position 14. This seems high, given the size of the field and the fact that MSN /Live Search finds it at position 61.

Can you, as a favor, run this search for me from your machine and see if you get the same results? I would appreciate it.

Thanks for the comment

Well, in fact you can influence the PR. It is not as easy as influencing the Technorati or Alexa ranks, but it is feasible. If there are more websites (with great PR) linking to your site (and not too many others), then your PR will increase (of course, it will take some time).

Regarding SERP (P is for “Page”), it is not influenced by your search history. Normally, if you search on different computers, with different cache, you should obtain exactly the same SERP (maybe I misunderstood you).