Things couldn't be better on "Steven's Untitled Rock Show."

Cameras are rolling, the Princeton-based band Saves the Day is chatty, and VJ Steven Smith is as charming and impeccably coiffed as ever.

Then guitarist David Soloway lets it drop. Out slips an S-bomb.

"I thought [it] was OK," Soloway says, apologetically.

The offending word will have to be bleeped, but in a way, it is OK. When you're Fuse, a cable music network vying to be edgier than MTV -- when you have a list of curse words that guests can use -- you clearly want limits to get pushed.

The challenge for Fuse is to walk the increasingly thin line between hip and crass, witty and snarky, new and established without grossly offending or pandering to the network's key 12- to 34-year-old demographic.

It's a difficult task. And Fuse is testing its boundaries like never before with Tuesday's debut of four new shows, which include a strip-tease dance-off and a British adult cartoon said to be "sicker than South Park."

So far, though, Fuse's gambles have paid off. In three short years, the network has edged its way into about 43 million homes nationwide.

But Fuse is hardly resting on its laurels. In fact, it recently hired David Weier, 38, as its new vice president of music and talent relations. His job is to find out what bands drive high school and college students wild -- often, that means being ahead of the curve in identifying future rock stars.

"Twelve to 24 [year-olds are] extremely passionate, which also means they are extremely fickle," Weier explained over the sound of the Editors' debut CD during a recent visit to Fuse's Manhattan studio. "If we were right on Tuesday we would be wrong by Thursday.

"And they don't want to be told what's cool."

So what's Weier's strategy?

"The secret formula is paying attention," he said.

And Fuse pays attention in a few key ways.

To identify the next big bands, Fuse employees do what helped the major record labels become successful: They regularly play the role of A&R reps, frequenting rock concerts that attract large audiences of young people -- such as next month's Bamboozle Fest in East Rutherford.

Recently, Weier said, the network aired videos by Coheed and Cambria after seeing teens wearing the band's gear at a radio station's Christmas concert. Weier added with pride that Fuse was playing My Chemical Romance and Fall Out Boy videos before they went into heavy rotation on MTV.

The station also monitors public opinion through text messaging and the Internet. Viewers can vote on everything from which videos they want to see to what the title of a new show should be (Steven's show was titled "untitled" because that's what viewers wanted).

And with Fuse's TXT TV shows, fans can send text messages with thoughts, relationship issues, gripes and more, and see them scroll across the bottom of the screen.

"The whole experience that we are trying to create is interactive," said Fuse President Andrea Greenberg. "So this is just one part of what we are doing."

Yet another strategy the Fuse folks employ is perhaps the simplest: They watch MTV.

Many of Fuse's executives once worked at the Viacom music giant, or at its sister network, VH1. Employees use the channel as an example of what can work, what doesn't and what used to work but now isn't being done.

So what works?

Well, like MTV, Fuse casts young, good-looking people with personality as its VJs. (Argentinian-born Marianela, the friendly, outspoken host of "Daily Download," is known as "America's hottest VJ" and has appeared with Fuse-mate Juliya in Maxim.)

Also like MTV, Fuse has a video countdown show with a live studio audience, intimate in-house performances and a large building with huge picture windows and video screens.

But the new facade of its Penn Plaza building -- unveiled earlier this month -- has the studio windows at street level, making featured bands easier to see by passers-by than those on "Total Request Live." Fuse also has a ticker that displays e-mails and "shout-outs" from Fuse fans.

The bands Fuse highlights also tend to have more indie rock cred, while MTV has more established bands.

That's no doubt somewhat out of necessity. According to the Cable Television Advertising Bureau, MTV and its more video-centric offshoot MTV2 are seen in about 387 million homes worldwide -- nine times as many as Fuse.

As a result, bands may be more likely to choose MTV's "TRL" over "Daily Download." And MTV is indeed making bands choose -- it has reportedly forced several acts to sign exclusivity contracts that prevent certain videos from being played anywhere but MTV.

But Fuse is also highlighting proven indie bands that are becoming, or have recently become, mainstream. For example, to help unveil its new street-front studio, Fuse chose Franz Ferdinand, which came up through the same independent British label now hyping the Arctic Monkeys.

And it's all paying off. Since the network's 2003 debut, its audience has grown exponentially. If this pace keeps up, Fuse will reach MTV status in fewer than five years.

"They killed alternative rock," said VJ Steven, referring to both New York radio stations and other music video stations that have lately turned their attention to more lucrative genres such as pop and hip-hop. "And that just left a void that we are going to dive in there and take."

E-mail: holahan@northjersey.com