Because if you turn it on its head and start looking at the net.porn, sooner or later you have to ask, Is whatever is depicted here happening on my beat? ICIU isn’t about porn (the war on porn is long since lost, though none dare admit it) so much as it’s about Internet memes— random clumps of bad headmeat that have climbed out of their skulls to go walkabout on the web. Often they’re harmless—a craze for silly captions on cute cat photographs—but sometimes they’re horrendous (p. 44)
Rule 34 is set in near-future Edinburgh: it's a loose sequel to Halting State, and is told, like the earlier novel, in three distinct second-person narrative streams. Inspector Liz Kavanaugh is investigating the latest in a series of improbable deaths which involve domestic appliances; Anwar Hussein is an identity thief (retired) who finds part-time legitimate work as the honorary Scottish consul for the Independent Republic of Issyk-Kulistan; The Toymaker is an enforcer for the Operation, much given to reveries concerning rape machines and lizards in designer suits.
As usual with Stross's novels, there's a hell of a lot crammed in: meditations on identity theft, virtuoso riffs on the theme of 'if this goes on', sharp images of a very credible future, sly asides. Stross gives us 'the obligatory state-owned Tesco Local'; suburban cannibalism made possible by medical tissue incubator tanks (cannibalism's not illegal in Scotland: gosh, I never knew that); mutant ninja genetically engineered superyeast. The second-person narratives offer ample opportunity for infodumps, opinion and polemic, without these feeling too much like authorial intrusion.
One aspect of this novel that I particularly admired is that, while nobody's defined by their gender or sexuality, the usual tropes are turned around. There are few heterosexual characters -- Dorothy Straight, Liz Kavanaugh's on-again-off-again ex, is not an example of nominative determinism -- and at least one of those is completely batshit. (Technical term.)
Very readable, pacy and funny: also thought-provoking, dark and packed with well-reasoned speculation.