Walkaway

by Cory Doctorow

There were vast surveillance nets sucking up every packet that traversed both the main walkaway trunks and the most highly connected default nodes, looking for a variety of keywords, anything that could be fingerprinted as characteristic of Iceweasel or her previous network access, which had been retrieved from the inconceivably vast databases of captured net-traffic. From her typing patterns to the habitual order in which she visited her favorite sites to the idiosyncrasies of her grammar, syntax, and punctuation, the surveillance-bots were sieving the network torrents for her.

But yeah, they need to inject you with a vaccine to track you.