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 131 million domains
Google Analytics: 20 115 700 sites
Google AdSense: 6 312 590 sites
Yahoo Publisher Network: 33 350
Yandex Direct: 27 475