The world's most famous corporate blogger, Robert Scoble, credited with helping to break down a siege mentality at his employer, Microsoft Corp., confirmed on Sunday he is leaving to join a recently formed Silicon Valley Internet media start-up.

Scoble, 41, said in a phone interview that he will join PodTech.net, a Menlo Park, California, start-up that earlier this year began "podcasting," or broadcasting over the Web, video interviews recorded with technology industry luminaries.

Starting in July, Microsoft's best known non-executive employee will become PodTech vice president of content, in charge of creating shows for the new medium in which computer users watch television-like interviews over the Web.

While earning Microsoft a newfound reputation for openness that counteracted its reputation as arrogant business partner, Scoble also came to define the paradox of the corporate blogger as both personal commentator and informal corporate spokesman.

Using his blog as a soapbox, Scoble came to personify a new style of corporate honesty in which he publicly spoke his mind on controversial topics. He was often willing to judiciously criticize Microsoft or praise its most fierce competitors.

Scoble, a software marketer who picked up on the emerging blogging trend in 2000, said he had told Microsoft Chief Executive Steve Balmer that he wanted to "put a human face on Microsoft and he took me up on that."

Scoble will now take his unique style and experience and try to create new avenues for podcasting to impact both the personal and corportate world.