Research conducted by UberCEO.com, a blog that comments on CEO issues, found that only two CEOs on Fortune's 2009 list of the top 100 CEOs have Twitter accounts and 81 percent don't have a Facebook page. Perhaps even more surprising, only 13 have profiles on LinkedIn, the networking site for business professionals, and only three of those have more than 10 connections.

And not a single Fortune 100 CEO has a blog.

Berkshire Hathaway's Warren Buffet and Procter & Gamble's Alan Lafley are the only two CEOs with Twitter accounts, according to UberCEO. Buffet has 7,441 followers, but he's not following anyone on the site. (Does Warren Buffet need to follow anyone?) Lafley has 33 followers and has never posted an update.

No CEO in the top 20 from the Fortune list has a LinkedIn profile. The 13 who do include Sunoco's Lynn Elsenhans, Bruce Johnson at Sears, Dow Chemical CEO Andrew Liveris, Allstate's Thomas Wilson, Mary Sammons at RiteAid and Motorola CEO Gregory Brown.

But the study found that even many of those accounts are largely inactive with few listed connections and outdated information such as listing old titles. Not surprisingly, CEOs of IT companies have the most active LinkedIn sites, including Dell CEO Michael Dell (more than 500 connections), Ingram Micro's Gregory Spierkel (213 connections) and Cisco CEO John Chambers (82 connections)

The 19 percent of CEOs who have a Facebook page have "a dismal number of friends," UberCEO said. Bank of America's Kenneth Lewis has only 13 (a good bet Federal Reserve Chairman Ben Bernanke isn't one of them), while John G. Stumpf at Wells Fargo and Vikram Pandit at Citigroup only have 12 and 8 friends, respectively. (Bankers, after all, aren't terribly popular these days.)

Exxon Mobile CEO Rex Tillerson is totally friendless.

The research eliminates accounts on social networking sites that UberCEO suspects may be fake, such as LinkedIn accounts for News Corp. CEO Rupert Murdoch and Apple CEO Steve Jobs

The one site where the top 100 CEOs have a presence is on Wikipedia, where 76 percent of the executives have some kind of entry. But many of those have inadequate or outdated information, according to UberCEO. The Wikipedia entry for Valero Energy CEO William Klesse consists of his name and title.

UberCEO attributed some of the lack of social network utilization to fear of running afoul of regulations such as Sarbanes-Oxley " saying the wrong thing about a company's financial performance can get a CEO in big trouble these days. But UberCEO said executives are also missing out on an opportunity to use the sites to connect with partners and customers. Twitter, for example, "should be viewed as an extension of the communications outlets they're already using."

"The country's leading CEOs aren't anywhere near as connected as their employees, partners, executives and customers are likely to be," UberCEO said. "It gives the impression that those CEOs are distant, disinterested and disengaged."