While he's a fan of social media, Zecca says only about 50 percent of his network is on LinkedIn and, he stresses, "There is no substitute for face time."

Zecca does sometimes enlist the help of executive search firms, "if after, say, two months, our leads run dry." The ultimate goal, he says, is using "whatever resource will ultimately give us the best employee."

CIOs looking for key candidates appear to be spending more time on LinkedIn than their C-level counterparts. "When identifying candidates for key hires, I definitely start with my own professional network first and foremost," says Greg Saltzman, CIO at InVentiv Health, a global provider of clinical, commercial and consulting services to healthcare companies. "The majority of my professional network is on LinkedIn, and with my premium account I can extend my connectivity within the ­LinkedIn ­network."

"We are on a very fast-moving growth trajectory right now. Speed is of the essence in filling key leadership positions with individuals who are at the top of their game. When I hire someone I know and trust professionally, I have a solid understanding of their capabilities coming in and can tailor the position based on their individual strengths, which is critical at the current stage of InVentiv's corporate development," Saltzman says.

You can't be passive and expect to fill a key IT role within your organization. C-level executives are taking a scattershot sourcing approach, so mirror that and vary the channels you explore. Don't rest on your 500-plus-online-connections laurels.