Skip tracing tactics may be employed by debt collectors, bail bond enforcers (bounty hunting), private investigators, attorneys, police detectives, journalists or as a part of any investigation that entails locating a subject whose contact information is not immediately known.
Records that "skiptracers" use may include phone number databases, credit reports (including information provided on a loan application, credit card application, and in other debt collector databases), job application information, criminal background checks, utility bills (electricity, gas, water, sewage, phone, internet, and cable), social security, disability, and public tax information. These methods don't break any law because the information is freely available due to the nature of the business, whether it be debt collectors, bounty hunters, or other "skiptracers".
Even when no specific information is returned, public databases exist that cross-reference skiptracing information with others the "skip" may have lived with within the recent past. For instance, if previous records show a "skip" lived in the same house as a third party, the third party may also be "skiptraced" in an effort to locate the "skip".
One example of this type of scenario would be an unlicensed "company" selling cell phone numbers or records to anyone with money. This is obtained by the abuse of social engineering/pretexting methods which are normally used by enforcement agencies for the common good when information can not be acquired by more direct means. Cell phone data should be legally acquired by the use of a subpoena.