LinkedInA free site, although registration is required. Create a profile page and then invite others into your network. When someone joins your network, you can "connect" with those in their network. Build your network and over time, you'll be able to search for and connect with people at hundreds of thousands of organizations. LinkedIn members can also see over 150,000 profiles of companies and nonprofits on LinkedIn. These profiles offer a concise overview of a company’s industry data (size, location, revenues, etc.), along with data culled from LinkedIn such as common job titles, median age, and median tenure. Users are also shown a list of LinkedIn users in their networks (up to 3 degrees away) who work at a company, plus a list of new hires, recent promotions and changes, and jobs posted on LinkedIn.