When a user visits a Web site, her browser may be instructed to visit other third-party domains without her knowledge. Some of these third-party domains raise security, privacy, and safety concerns. The Strider URL Tracer, available for download, is a tool that reveals these third-party domains, and it includes a Typo-Patrol feature that generates and scans sites that capitalize on inadvertent URL misspellings, a process known as typo-squatting. The tool also enables parents to block typo-squatting domains that serve adult ads on typos of children's Web sites.
http://research.microsoft.com/URLTracer/