A personal recommendation trumps everything else. Having someone your employer knows say you are the right person for the job counts for more than your resume or past job performance. When I interview for a job most people start by asking me, “who do I know who knows you?” The set of people who I could give as answers to this question make up my personal network.
By the time you are looking for a new job it is unlikely a new contact will help you. You need to cultivate relationships throughout your career. Every person you meet could be the one who helps you get your next job. The more people you know the better