NBR | Now Hiring? | PBS

This PBS clip reports that, although the economy is struggling, there are many open job positions that have been difficult to fill.

Aon, an insurance/risk management firm, is having difficulty finding candidates for 500 positions. They search social networking sites for candidates who work at Aon competitors and their VP says they prefer hiring working candidates.

Cision, a PR company, is looking to hire research and sales professionals with a specific set of skills. What other methods should these companies use to find good candidates?