I've been writing this column regularly for over three years, and for this week's column I decided to throw you a curveball. Instead of starting off by talking about the challenges facing CIOs, I'm writing about the challenges facing CEOs.

The great CEOs typically wake up at night worrying about how their companies can stay ahead of the competition by innovating new products, opening new markets, expanding traditional markets, growing revenues from sales, increasing operational efficiencies and improving the bottom line. It's a lot to worry about!  

But in the final analysis, CEOs are judged by how well their companies perform in competitive markets. If your company isn't among the leaders, your tenure as CEO will likely be short, and not particularly sweet. That's why CEOs wake up at night and worry about how well their companies are doing compared to the competition.

Why should modern CIOs be concerned about what's keeping their CEOs up at night? The answer is simple: To a far greater degree than ever before, the CEO's strategy for success depends on the CIO's ability to deliver technology solutions that create real competitive advantages for the company. The days when the CIO's "customers" were mostly internal business users (aka "captive users") are over.

Today, the CIO's "customers" tend to be the same as the CEO's "customers." When the CEO talks about "customers," he or she is talking about paying customers who generate actual revenue for the company. The fact that CEOs and CIOs now have the same "customers" represents a monumental shift of epic proportions, with major implications across the entire enterprise.

In addition to tactical issues, it presents a host of strategic challenges for the CIO. Enabling and executing the CEO's strategy for winning in competitive markets is fundamentally different than making sure that everyone in the company has an email address. For the CIO, the stakes are much, much higher than ever before.

That's the reason why the CIO's prime responsibility is making sure that he or she is totally aligned with the CEO. In the modern enterprise, there is no appreciate difference between business strategy and IT strategy. If those two strategies aren't precisely aligned, the enterprise will not achieve its goals and the board will begin looking for new senior executives to get the job done right.

For the first time in history, the fates of the CIO and the CEO are fully intertwined, intermeshed and interdependent. Whatever keeps the CEO awake at night should keep the CIO awake too.