Final answer:
LinkedIn and similar personal online networks are the most effective sources for finding passive candidates, providing access to a broader pool of qualified individuals who may not be actively job seeking.
Step-by-step explanation:
The best online recruiting source for finding passive candidates is personal online networks such as LinkedIn. These platforms provide an environment where professionals maintain their profiles, making it easier for recruiters to find potential candidates who may not be actively looking for a job but are open to new opportunities. LinkedIn, in particular, has become a valuable tool in the recruitment process, changing how both job seekers and employers approach the job market. Additionally, the use of social networking sites complements traditional recruiting methods by allowing recruiters to tap into a larger pool of qualified individuals who may otherwise be inaccessible through conventional channels such as job fairs or employment agencies.