As a strike by Hollywood screenwriters throws dozens of television shows into production turmoil, a new series aimed at TV's target audience of young adults is headed for launch on the Web -- not television.

On Sunday, Emmy-winning TV show creators Marshall Herskovitz and Ed Zwick (thirtysomething, My So-Called Life) begin Webcasts of Quarterlife, a weekly saga of six young artists carving out careers in a big city.

The debut of Quarterlife, the first original Webisode from A-list TV creators, comes as the Writers Guild of America presses studios for a bigger share of revenues generated from movies and TV shows delivered over the Internet.

Quarterlife differs from network shows like ABC's Desperate Housewives, which can be downloaded from Apple's iTunes. It is an original series made exclusively for the Internet, presented initially on MySpaceTV and a day later at quarterlife.com.

The Web-based drama points to the Internet's growing prominence as an outlet for mainstream entertainment, and highlights the importance of the Web to screenwriters and the broadcast networks.

Herskovitz and Zwick developed Quarterlife outside the TV networks and studios, investing their own money in the venture to maintain creative and financial control over it.

That is the whole reason we've done this, Herskovitz told Reuters on a recent visit to the set of the Web series before the WGA's 12,000 members went on strike on Monday.

(Studios and networks) own the whole product and exert way more creative control than they did in the past, Herskovitz said. They took away our ability to be entrepreneurial.

The major networks and studios are getting into the digital game themselves. The producers behind the ABC hit drama Lost are creating a spinoff of that show tailored especially for mobile phones, with the first mobisode due to show up on Verizon Wireless in the next couple of weeks.

WHAT TV NETWORK?

Quarterlife cast members, who are in their 20s, do not view the Web as substandard to TV, and like many of their peers, are excited by the possibilities of Web video.

We're reaching an audience that is not necessarily watching on a TV network, said Bitsie Tulloch, who plays the lead role of Dylan on the show, and worked on the Web sensation lonelyGirl15 as well as on such TV series as Lost.

Herskovitz and Zwick have tailored Quarterlife for the Web, blending the personal relationship stories they did best in programs like the high-school drama My So-Called Life with a saga centered on Dylan, a blogger, and her best friends.

Other key characters in the 36, eight-minute Quarterlife episodes include filmmakers Danny and Jed, actress/bartender Lisa, geeky Andy, and Debra, who still lives with her parents.

Herskovitz said Quarterlife will be free of constraints on language and other risky content TV networks often censor. On quarterlife.com, characters and fans will interact with the goal of building a tight-knit social networking community.

The response from advertisers has been way beyond what I thought. We've already made deals to cover production costs, Herskovitz said. They believe it is going to take off.

He declined to offer details, but Dina Kaplan, chief operating officer of Web video site, blip.TV, said Webisode ad revenues range widely from hundreds or thousands of dollars to tens of thousands depending on the type of ad.

In the first half of 2007, online ad spending overall surged 27 percent to almost $10 billion, according to the Interactive Advertising Bureau. Industry analysts expect it to grow at 25 percent to 30 percent for the whole year.

It's the wild, wild West, Kaplan said. And everybody wants in on the action, especially Hollywood's writers.

(editing by Steve Gorman)