EU Recommends Slashing Search Data Retention
"They do _not_ need that to refine their searches. If I search for, say, "Oracle auto-tuning", that's that. I expect the same result regardless of what my IP is, regardless of whether I searched for "WebSphere XA configuration" before, or "Fluffy tail buttplugs" or whatever. You can tune the search with just the search string. You don't need to track me for that."
First, I'm not defending Google's right/desire to keep any of this data...
That said, you are wrong. Search results are not idempotent, they change depending on your language, which data center you're talking to, and they will certainly change over time. If I search for "chevy parts" and then I immediately search for "impala", I'd rather see pages about Chevy Impalas. If I had just searched for "african wildlife" then I'd rather see results about the animals. If I search for Bush from U.S. I'd expect more weight given to pages about the President, while people in other english-speaking countries might get more landscaping pages.