It’s also called the Invisible Web or Dark Web—the parts of the Internet that are not indexed by standard search engines. Like an iceberg, this submersed, unseen part of the Web is many times more massive than what can be seen.
For those adept at doing background checks, the Deep Web can accessed. One of the most common Deep Web activities is to PRC someone—a public record check for arrest, traffic and divorce records, bankruptcies, liens, and the like.
A story in The Village Voice reports that a blog of an ex-Scientologist asserts that the creators of South Park, Trey Parker and Matt Stone, who ridiculed that organization on their show, were PRCed. This SOP for digital opposition research.