johnhh - 9:20 pm on Oct 30, 2010 (gmt 0)
I used to be involved in multi-dimensional analysis of time dependant variables based on "user" responses.
Often if you actually relied on the statistical result you missed the "big picture" and often the manual conclusions were based more on gut feel than anything.
Conclusion : you can only profile where the user "fits" a specific statistical conclusion set, or several sets - so I would agree with Shaddows - Google is trying to fit your site within a set of contexts
Proof: how many times have you seen your site appear in searches for which your site pages are not specific aimed at ?