Aetna CEO Mark Bertolini recently was drawn into a public argument about health insurance when Arijit Guha, a 31-year-old cancer patient, challenged the company over its refusal to pay his medical bills once he reached his plan’s coverage limit.

Guha’s campaign went viral, and Bertolini ultimately agreed to cover the bills.  To most observers, Bertolini lost – a Gulliver-esque CEO brought low by social media’s Lilliputians.  But Bertolini emerged a winner, too.

Guha began his campaign with a modest website and blog, where he sought to raise funds to pay for his cancer treatment.  Calling it the “world’s most important bake sale,” Guha took to Twitter to challenge Aetna and soon caught the attention of the Washington Post and NPR. Aetna ultimately agreed to extend Guha’s coverage.

Observers called the drama a “public relations nightmare” for Aetna.  But while it had its uncomfortable moments (who wants to be seen opposing a cancer patient?), Aetna handled it well.  More than that, Bertolini emerged as a compassionate, engaged leader willing to take action to solve a problem.

In reading the exchanges on Twitter, two things about Bertolini’s actions stand out:

1.  He responded to the broadsides.  Twitter makes it easy to take shots at a company, especially on a highly charged public issue like healthcare.  Most companies don’t respond to these drive-by shootings or simply offer up a PR or legal affairs executive (which is where Aetna started with this case).  But Bertolini himself responded, and he gave as good as he got, replying to comments about Aetna’s profitability, the cost of health insurance, the strains in the healthcare system – and what was being done to help Guha.  The dialogue was heated at some points but Bertolini didn’t flinch.

2.  He humanized the company.  We love to hate insurance companies, and they constantly supply us reasons to do it.  They’re seen as impersonal, secretive and hopelessly bureaucratic.  Yet here was a real person – the CEO, no less – handling a customer issue in real time, for everyone to see.  Turning around entrenched views about Aetna or any insurer doesn’t happen overnight, but Bertolini has made a great start.

Unlike Bertolini, most CEOs have so far steered clear of social media.  According to a recent survey, 70 percent of CEOs have no social media presence at all.  Sure, Rupert Murdoch and Richard Branson are notable tweeters, but the vast majority of corporate chiefs are leaving social media to the marketing, human resources and IT departments.

It’s not hard to see why.  Sustaining a social media presence takes real commitment and a willingness to offer –and hear – candid commentary.   But there can be real gains for CEOs who are willing to take the risk and venture into social media.

Aetna’s Mark Bertolini has shown them the way.