TheMadScientist - 9:56 am on May 2, 2011 (gmt 0)

...hire people use proxy servers and kill cookies to do it 400 times a day from different IPs.

I doubt it would go unnoticed.

Unless they restrict it to users who have Google accounts...

They do.

...and are logged in at that exact moment...

You have to be.

The only statistic I see, which is about 90% of what is of interest, is whether a person clicks on a link, goes to that site, and does not perform that search again within the next minute or so.

And is compared relatively to clicks and behaviors on other closely related results?

Which I suppose they could track with cookies... but doesn't that cause privacy issues?

I guess you haven't heard if you want privacy you shouldn't be online and definitely shouldn't use Google? lol

Are they allowed to store searches by IP or computer?

They personalize results by default; I think they're storing searches by anything they can identify a user by.