LinkedIn is a tool you need to begin exposing your students to. The business/professional social network is increasingly being used by employers to find jobs and for social networking. Perhaps best for career services and alumni offices, LinkedIn is a great way to encourage cross-generational network building.
LinkedIn is also increasingly moving into the higher education space with a number of tools for college and school discovery and recruiting. The following video comes from LinkedIn and highlights many of their efforts in broadening the reach of their platform: