NEW YORK (Reuters) - MTV Networks plans to make every clip from every episode of the hit animated comedy "South Park" available for free online next year as part of a strategy to reach consumers everywhere.

The decision from the biggest division of media conglomerate Viacom Inc follows on the heels of the "The Daily Show with Jon Stewart," whose popularity online has helped boost television viewership.

MTV Networks' Comedy Central channel network began offering in October some 13,000 "Daily Show" videos dating back to 1999.

Presenting versions of TV shows online has not hurt television ratings, and may have actually helped.

"One does not diminish the other by any stretch of the imagination. That is kind of our hat trick," MTV Networks Chairman and Chief Executive Judy McGrath said at the Reuters Media Summit in New York on Wednesday.

In August, Comedy Central signed an extension of a deal with "South Park" creators Matt Stone and Trey Parker, and agreed to create a new joint venture to spread "South Park" materials across the Web, on mobile phones and video games.

So far, the venture, SouthParkStudios.com, features a small collection of video clips from the show.

Bernstein Research said on Wednesday cable network ratings at several of Viacom's channels spiked in November, led by MTV, reversing a steep decline earlier in the year.

Other shows from the 20-year archives of MTV Networks could also get the same online treatment, but executives stopped short of naming other properties.

"'The Daily Show' was the first out of the gate and it's been a big success and it's a nice little model for us to follow," said Mika Salmi, MTV Networks president of global digital media. "There's no limit to which shows we can use at this stage."

Once criticized for moving slowly to establish itself online, MTV Networks has aggressively expanded its digital media presence over the past year by building new Web sites and communities on the Internet and over cellphones globally.

Executives said its television content has drawn visitors to its digital properties, such as virtual world Nicktropolis and ComedyCentral.com.

But new features that let viewers grab online videos to install on a viewer's own Web page, and other tools to swap messages with content creators or other viewers, have convinced viewers to stay.

Most big TV networks, led by Walt Disney Co's ABC, have offered full-length episodes of current-season shows such as "Desperate Housewives" online, shortly after their first public broadcast.

Comedy Central's "Daily Show" is one of the few programs that offer free access to a deep archive of back videos.

Hulu, an online video joint venture of News Corp and General Electric Co's NBC Universal, is testing a service that offers portions of recent archives of hit shows.

"Clearly across MTV and VH1, we have two decades of all kinds of things from music and popular culture," McGrath said, responding to a question about what else could be offered.

Elsewhere across the company, Salmi said a just-launched mobile video social network, myMTV in Japan, is being considered for expansion into other regions, possibly the United States.

MTV also began selling new music-based video game "Rock Band" last week, and executives said copies of the game were "flying off shelves." The game competes against the popular "Guitar Hero" franchise, owned by Activision Inc