UNIVERSAL CITY, Calif. -- Watched any good Web series lately?

If you don't know what a Web series is, you're not alone. But more of these short-form programs created for online are getting made, including today's 9 a.m. debut of the music-themed romantic comedy "Rockville, CA" on TheWB.com.

Actress Megan Mullally, who starred on TV's "Will & Grace" as the boozy Karen, hadn't heard of TV shows produced exclusively for the Internet until shortly before she starred in one, the comedy "Children's Hospital" on TheWB.com.

"We were in Oklahoma City for Christmas and then in a small town in Illinois to visit my in-laws and we were talking about this Web series we did," Ms. Mullally said of her winter travels. "And people were like, 'What's a Web series?' "

If Hollywood studios have their way, that question will evaporate as computers and TV sets eventually merge into a single device.

What began with user-generated video on sites like YouTube has grown in recent years to be a supplemental platform for viewing prime-time TV shows, whether it's pay-per-download sites such as iTunes, streaming on network-branded sites like ABC.com or streaming on affiliated sites such as the NBC-Fox joint venture, Hulu.com, whose CEO, Jason Kilar, grew up in Murrysville.

If posting TV shows online was a first generation effort, creating original content, even series, for online viewing is becoming the focus. Initially created by amateurs or independent producers, entertainment conglomerates are now making Web series part of their business.

In addition to independent sites such as FunnyOrDie.com, which HBO invested in last summer, Sony launched Crackle.com in 2007 and Warner Bros. debuted TheWB.com last August.

Using the brand of the now-defunct WB television network, The WB.com has launched several series. In addition to the comedy "Children's Hospital," there have been soaps ("Blue Water High"), reality shows ("Boy Wearing Makeup"), mysteries ("Sorority Forever"), and, beginning today, "Rockville, CA" from Josh Schwartz, executive producer of TV's "The O.C." and "Gossip Girl."

Set in a fictional Los Angeles rock venue, "Rockville" follows smart hipster Hunter (Andrew West) as he embarks on a romance with label executive Deb (Alexandra Chando). Twenty episodes were produced, each lasting no more than six minutes and with a different modern rock performance.

Mr. Schwartz said "Rockville" seemed more suited to the Internet than conventional television because of the emphasis on music, which became popular online even before video. The project also proved to be a learning experience for a producer steeped in the ways of traditional television.

"Learning how to adapt and tell stories that made sense in four- or five-minute chunks has been really exciting and incredibly creatively fulfilling," he said in January.

So far, no series has made as big a splash as last year's musical-comedy "Dr. Horrible," which starred Neil Patrick Harris ("How I Met Your Mother") and Nathan Fillion ("Castle") and was created independently by a team that included Joss Whedon ("Buffy the Vampire Slayer"). Attaining a "Dr. Horrible" level of buzz may be the Holy Grail among online programmers.

The key to success, according to executives at Crackle.com, is to create high-quality entertainment with which advertisers want to associate their brands.

"Crackle is Sony's next-generation TV network," said Eric Berger, senior vice president of digital networks for Sony Pictures Television, at a January press conference. "It's the marriage of the traditional cable network sensibility with an immersive, on-demand service."

These Internet shows, free of the Federal Communications Commission constraints on broadcast networks, can include unbleeped profanity (an early episode of "Rockville" includes the f-word). But when advertisers are targeting young males 18-34, as Crackle does, profanity may be seen as a plus. "We need brand-friendly content," said Michael Hayes, managing director of Initiative, a media services company. "With YouTube, only 3-to-4 percent of all that video that you see is advertising supported."

There are ways to measure online viewing, but at Crackle, there's no specific number of streams that determines success for a program.

"Each show has a different metric and a different threshold," Mr. Berger said. "We're very pleased with the shows that have launched and how they are tracking and we're looking at revenue streams beyond advertising on the site."

At least one Crackle series, the action-drama "Angel of Death" starring Zoe Bell and Lucy Lawless, will be released on DVD.

For writers and actors, online series offer few of the layers of network and studio bureaucracy that they encounter on TV productions.

"What drew me to it was the freedom and the creative opportunity," said Mr. Schwartz. "It really felt like we were putting on a show. ... There was a lot of room for experimentation and play."

That putting-on-a-show vibe was mentioned by a half-dozen Hollywood actors and writers during over the course of several days of interviews in January.

Ms. Mullally didn't recall being paid for "Children's Hospital" -- "it's, like, a $2 budget," she said -- but she wasn't doing it for a pay check.

"I love doing low-budget stuff where everybody comes together and it's just like putting on a show in your backyard," she said. "The hair and makeup girl was as invested in it as the actors and the director was. Everybody is doing it for nothing, which makes it a level playing field."

Business models for Web shows vary. WB.com executives said everyone who works on their series is paid and some programs, including "Rockville," are made under the aegis of AFTRA, an actor's union. The one commonality is that all Web series cost a fraction of prime-time TV series, which run more than $1 million per episode for half-hour programs and more than $2.5 million per episode for dramas.

"We're doing 22 episodes for what's in the mid-six-figure range," said Bob Kushell, executive producer of ABC's "Samantha Who?," who moonlights as a talk show host on Crackle's "Anytime with Bob Kushell," whose new season debuts today. It tapes five-minute episodes in a studio built in his brother-in-law's garage.

Writers who come up with videos for FunnyOrDie.com are paid but the big-name stars who appear in these videos are not. "How do you go to Jack Black and say, 'We're going to give you 10-grand to do a video?" said Funny Or Die writer/producer Chris Henchy ("Entourage"). "It doesn't do anything." Instead, it's about the experience of collaboration, which is how Funny or Die convinced Jack Black to join Allison Janney, Neil Patrick Harris and a host of other stars in "Prop. 8: The Musical," a satire of the gay marriage debate in California.

Web series also serve as an inexpensive testing ground for prospective TV shows. Executives at TheWB.com said they've had interest from networks in some of their programs and next week ABC debuts the comedy "In the Motherhood," which began as an online series.

Mr. Schwartz of 'Rockville, CA.,' said he couldn't begin to predict where online TV is going.

"I think part of what makes it exciting is that it's evolving, and I think this is a step in that evolution."