Can Google aggregate everything you've ever posted anonymously online based on writing style?
jbester: It is no doubt possible.  I've done something similar to this on a single forum 3 or so years ago and had reasonably interesting results.Basically, I scraped the site, removed formatting/spacing/dead-words, stemmed  (using a modified porter), constructed a matrix of word-frequencies per post.  After which I did several various analytical techniques (statical, geometric, etc).  The net result from using a blended method was able to identify several most aliases of board posters  However, the issue google would no doubt have is sampling size.  In a small enough sampling size quirks work as identifying characteristics, in a larger dataset you would no doubt see clusters of people who have similar backgrounds (e.g. education).