Google results get "better" (depending on your definition of better) as you go in very specific ways. When I browse I clear cookies every time a tab is closed and I never log into Google just for searching. I've noticed at work I'll be googling for programing stuff and if my session gets "stale" (been doing a bunch of searches without closing the tab) I notice Google starts making assumptions about what I want. For example, if I Google a generic programming term say "string," on a stale session Google will assume the string I want is programming rather than, say, crafting or physics, and the string I want is the language I've been Googling in my last few search terms. So if I googled "string" in a fresh session I get a couple generic Wikipedia pages and some references from various programming language. If I Google "string" in a stale session Google "knows" I'm looking for the Java string so they will show me Java string results. If I wanted those same results I'd have to Google "Java string." It does make you lazy at searching though because you start thinking "Google knows what I'm talking about."