The internet has obviously changed our virtual lives beyond recognition -- heck, no-one had "virtual lives" before the internet -- but it's also had a marked, if more subtle impact on our physical surroundings.
Ingrid Burrington's project "Networks of New York" is an attempt to decode some of the internet infrastructure hiding in plain sight -- objects and symbols that fill the urban landscape, but which you probably don't pay attention to (and wouldn't recognise even if you did).
On Burrington's website (and in her book), she details curiosities like the different kind of manholes and handholes you encounter in NYC, not to mention all the different kinds of antennae that live on lampposts and subway platforms. There's also a good beginner's guide to street markings, the innocuous graffiti that gives you a clue to what sort of pipelines might be running below your feet.
The website is a fascinating checklist of internet infrastructure to begin with, but the $US25 book -- currently up for pre-order -- promises a deeper burrowing down the rabbithole, with more explanations behind each item on the internet checklist. [Networks of New York via Gothamist]