Just when I was getting tired of reading about personal branding, I had a conversation with a hiring manager that reminded me why personal branding and marketing through social networking websites is so important if you're looking for a new job. A strong personal brand enables hiring managers who have jobs to fill\u2014jobs that you may not know about\u2014to find you. Marketing yourself allows you to tap into the "hidden job market" and make yourself visible to organizations that may need your expertise. Personal branding truly helps you stand out. (CIO.com has a ton of articles on personal branding. I recommend Personal Branding: 8 Tips that Will Help You Stand Out, Managing Your Reputation Online, and Mark Cummuta's latest CIO Job Search blog on marketing your expertise.)Erik Huddleston, the CTO of Inovis, a B2B data exchange, is the hiring manager I interviewed this morning. He explained how he uses social networking websites to recruit people for jobs, and his explanation illustrates the role that personal branding and social networking play in the job search and hiring process. Huddleston says that when he has a position to fill, he proceeds directly to LinkedIn to identify professionals in key staff members' networks who may be right for the job. He does the same on Facebook. If the people Huddleston identifies are also on Twitter, he checks out their Twitter streams, too. "Looking at their background, their skill sets and what they're talking about on their Twitter feeds, I can get a pretty good feel for people who sound like they'd work well," he says. Huddleston isn't the only hiring manager using the "LinkedIn first" approach. David Perry, the author of Guerilla Marketing for Job Hunters, says many other recruiters and hiring managers use LinkedIn to pre-screen candidates. (See The Two Websites Every Job Seeker Needs to Join.) If you have a strong LinkedIn profile that communicates your brand, expertise, accomplishments and unique value, you increase your chances of getting contacted about jobs that you don't even know exist because you stand out to hiring managers. By contrast, if you're not on LinkedIn or your profile is weak or out-dated, you're probably getting passed up for consideration by hiring managers and recruiters. (Find out if hiring managers are checking you out online.) For advice on creating an irresistible LinkedIn profile, see How to Improve Your LinkedIn Profile, Stand Out to Employers, Recruiters and LinkedIn Etiquette: Five Dos and Don'ts.