Sometimes you may want to find out who owns which website, and which other websites he own. (Try imagining Mr. JD owning rapejournal[dot]com, and ifightagainstrape[dot]com). If you want to track a website owner the best way to do this is by scouting thorugh his Google Analytics ID or Google Adsense publisher ID (if he uses them).
Here are a few services that show you how to view every website linked to Google Analytics ID or Adsense publisher ID of a website owner.
What are the implications of showing your Google Analytics ID?
If you engage in “anonymous” activities, e.g. hacking, whistleblowing etc, or security-volatile blogging, then your hidden identity may not be as hidden as you think, because using the same Google Analytics ID across multiple websites, which is the common case (say, in both the anonymous site and your personal blog for example) would mean that a simple search using any of these listed sites would reveal your identity immediately.
So, are you really anonymous as you thought you were?
Read further: How to protect your identity.