ABC is the only major broadcast network that is using the staff of its evening newscast to produce a separate and distinct daily program for a Web audience.

Over the course of 20 months, the Webcast has evolved from a basic distillation of the day’s news into an original program that incorporates video blogs, first-person essays and interviews.

ABC News’s main network competitors, CBS and NBC, are for the moment mainly using the Web to repackage their regular nightly news shows.

The “World News” Webcast does not have any commercial interruptions, though AT&T and Pfizer have run advertisements just before the podcast version starts.

“I feel less pressure to wear a tie, sit up straight, and make sure everything I say is perfectly enunciated,” Mr. Harris said. “I have an opportunity to be much closer to who I actually am, instead of the TV version of myself.”