From now on, everyone could be a spy at least on the web.
Simply enter website url, ip address, google adsense or google analytics code and find out what resourses belong to the same owner.
Free of charge!
Warning: the results may be very surprising...
More than 144 million domains
Google Analytics: 26 434 300 sites
Google AdSense: 7 316 160 sites
Yahoo Publisher Network: 33 617
Yandex Direct: 36 900