As TV networks paddle ahead with their online video plays, they are further extending their social media toe-dipping with short-message service Twitter. According to the WSJ, the U.S. networks CBS, NBC, ABC Family and MTV are using short messages—delivered via SMS, IM, email, or directly on Twitter’s site—to forge stronger links with their viewers.

While TV companies hope for reasonable advertising revenue streams on the back of their online TV initiatives, the Twitter tinkering is more about trying to tap into the viral marketing that’s become such a hallmark of Web 2.0. Twitter, the article notes, only has around 370,000 active users per month—a small chirp in the cacophony of CPMs and TV ratings. But Twitterers are often hooked into other social media outlets like blogs and are exactly the kind of folks the networks hope to get buzzing about their programs, not just to drive traditional TV viewing but also more traffic for their Internet initiatives.

Recent projects have included using Twitter to send registered users updates from the red carpet and after-parties for the MTV Music Awards. On the horizon, ABC Family plans to get actors and writers from its show “Greek” to send behind-the-scenes info during the filming season; and NBC is going the route forged by “Battlestar Galactica” and “24”: to use Twitter to link together a wider community online. The computer-geek star of “Chuck” will Twitter fans and will also try to drive traffic to other places like his MySpace page.

It’s encouraging to see Twitter coming up with a business model for its service, but the site (and the networks) will need to make sure that the messages do not stray too far into conventional show promotion, notes the article. Such crass commercialism could alienate the very people Twitter is trying to win over.