• by Gavin O'Malley  @mp_gavin, October 3, 2007

Fastening its top button, The Huffington Post reached new heights of professionalism this week with the appointment of its first chief executive officer. For the job, the liberal news site nabbed Betsy Morgan, who is leaving her post as general manager of CBSNews.com.

Huffington Post co-founder Kenneth Lerer, a former Time Warner executive, has served as the site's chief executive since its debut in mid-2005.

From those humble beginnings--if you can call the musings of Arthur Schlesinger and Alec Baldwin humble--HuffPo has emerged as the fifth-most-trafficked blog online, with 3.5 million monthly readers. (For context, CBSNews.com draws roughly 5.5 million visitors per month.)

Since securing $5 million in venture capital last summer, Arianna Huffington has worked to expand her brainchild with video content, as well as business and editorial staff additions.

Morgan's career shift comes as mainstream media struggles to adopt the technical prowess and agility of blogs and new media publishers, while the upstarts seek firmer organizational structures and business strategies.

"Both sides are moving toward the same point from different directions," said Phil Leigh, president of Inside Digital Media, a market research firm specializing in digital media.

But, added Leigh, the advantage lies with the upstarts who have less to lose and fewer institutional barriers to prevent change.

"The new competition has the edge because they're hungrier, they can take more risk, and there's more opportunity for growth."

The appointment of Morgan--who worked in business development at CBS before taking the top post at CBSNews.com in 2005--is part of HuffPo's ongoing strategy to establish itself as a mainstream media business.

James Smith came on earlier this year as HuffPo's first chief revenue officer. (Smith came over from AOL's Advertising.com, where he served as chief of publisher services.)

With Morgan, Huffington Post now has more than 40 full-time employees, including nine ad sales reps.

The site helped host an online presidential debate and vote -- a mash-up moderated by PBS's Charlie Rose, and conducted in partnership with Yahoo and Slate.

The site has also broadened its editorial scope to include sections on business, technology, entertainment, and lifestyles (religion, food, fashion, relationships, etc).