Recently-released research from the blog found that curiously-absent from the users of sites such as Facebook, Twitter, LinkedIn, Wikipedia, and blog sites were Fortune's 2009 list of the top 100 CEOs.

Only two had Twitter accounts, and 81 percent did not have a personal Facebook page.

Last year, we did a similar poll among the 2008 Inc. 500 CEOs. According to our survey, 31 percent of our business owners maintained a blog or presence on a social network.

We went back to a few of the CEOs on our list to ask them why they found SNS useful.

Michael Biggerstaff, CEO of Nxtbook Media, said of his blog last year, "Our clients love it, and lots of people in our industry pay attention to it."

He has since joined the ranks of Twitterers and gained 481 followers since his first tweet in early August of 2008, probably because he doesn't use it to shamelessly promote his company.

"We have a Nxtbook account that our marketing director uses for that, minus the shameless of course," Biggerstaff jokes. "I decided that [my account] would be more of a personal nature, observations about life or things about the company, cool things we do and awards we win. I will also tweet information from conferences that I feel is important or interesting for our staff primarily and then for the rest of my followers secondarily."

Brian Marr of design firm Wexley School for Girls said his blog's readership had spiked by 347 percent last year. Now with 409 Twitter followers, Marr extends his face of the brand through his profile, @bmarr, and uses it to advertise open staff positions and to search for photo shoot models.

"Customers crave engagement and dialogue with the brands they love, and Twitter is one of the ways you can help establish that," Marr said. "The key is remembering that you're walking into one big dinner party - if you start shilling products instead of engaging with people you might not find any seats at the table."