The study found that only two CEOs from Fortune magazine's list of the Top 100 companies and only 19 have . And none of the 100 CEOs were found to have a personal external blog.

"In our opinion, the top CEOs appear to be disconnected from the way their own customers are communicating," said Sharon Barclay, an UberCEO.com editor. "They're giving the impression that they're disconnected, disengaged and disinterested. No doubt, regulations such as Sarbanes Oxley and Reg-FD make CEOs cautious about communicating freely, [but] they're missing a fabulous opportunity to connect with their target audience."

The thought of a button-down type of business person twittering about his last meeting or spilling coffee on his $500 tie while being chauffeured to work might not be all that surprising.

However, an increasing number of executives at smaller firms have taken to Twittering and are staying connected with associates and customers on their Facebook pages. Zappos.com Inc. executives, for example, credit the use of such social media outlets by employees with helping to generate significant sales growth during the current economic slide. Of the online shoe and clothing store's 1,400 employees, 450 -- including CEO Tony Hsieh -- actively use Twitter to promote the company.

Analysts have noted that there's increasing pressure on companies and their executives to use Web 2.0 tools , Twitter and LinkedIn to stay connected with their customers and partners.