Google hacking involves using Google search operators and modifiers to identify vulnerabilities on websites. The document provides examples of common operators like cache:, link:, related:, info:, site:, intitle:, inurl:, intext:, and filetype:. It demonstrates how to use these individually and combined, such as "intitle:index finances.xls" to find Excel files indexed on websites. The goal of Google hacking is to search like a hacker to find sensitive information exposed online.