Equifax used its employment records database, The Work Number, to investigate and fire dozens of its own employees for working second jobs without approval. The company's investigation, codenamed 'Project Home Alone' and 'Project Page 12', used various methods to identify employees with multiple jobs, including reviewing work histories and activity records. Equifax's use of its own data to monitor employees has raised concerns about privacy and the company's trustworthiness with sensitive information. The incident highlights the growing trend of employers using data and monitoring tools to track employee activity and enforce company policies.