>"Since ADSL IPs tend to be pseudo-static these days this can be pretty accurate."
Don't forget what the Google Streetview rumpus, back in circa 2010, was all about, namely the collection of wireless data such as router MAC address, SSID's etc. Given all this information is also readily available to your browser, these could be used to further refine data and identify individual devices and their user(s).
Biting the hand that feeds IT
