You may have originally signed up on Facebook to keep up with friends and family, but professionals find that it and other social media sites are actually great tools for finding a job, too. The trick is that you have to be much more guarded and selective about what you say when you want to use social media sites for networking purposes. This might involve a major revamp of your profiles.
The most popular site specifically meant for professional networking is LinkedIn.com, where you can list your professional experience on your profile and make professional connections. You can ask your old coworkers and managers to write recommendations, which you can post on your profile. Also consider increasing your presence by participating in discussions relevant to your industry [source: Wilms]. Potential employers may happen to discover you on LinkedIn, or they'll likely find your profile there when considering your application.
In addition to increasing your online presence, Facebook, LinkedIn and Twitter are good tools for following companies you are interested in working for. If the company posts updates on such sites, read them regularly to keep up with its interests and direction. Becoming familiar with a company will give you leverage as you try to sell yourself to them.