IF the world is still spinning on its axis this Thursday, the Knick game at the Garden that night against the Bucks will mark the home team’s 328th consecutive sellout. That’s the equivalent of eight seasons without an empty seat in the house.

Which would make, you’d think, the job of Steve Mills, the Knicks’ marketing, financial planning and business affairs boss, an absolute layup.

After all, with the second-longest current sellout streak in the NBA, behind just the Bulls’ 510, a season-ticket waiting list 15,000 people strong and a storied history woven into the fabric of the city, you’d think Mills’ biggest problem would be getting the doors open on time and making sure there are plenty of T-shirts and replica jerseys at the souvenir stands.

You’d think.

Well, think again.

As the business team captain for the Knicks, the biggest and baddest brand in the Cablevision sports lineup, Mills is being called upon more and more to use that brand power to rev up the sales and profit engine of Cablevision’s weaker cousins.

Such as St. John’s basketball and other college hoop events at the Garden, boxing events at Cablevision-controlled Radio City Music Hall and Chase tennis.

Which means Knick fans can expect to be asked, through in-game announcements, e-mails, palm cards at seats and in various other marketing methods, if they wouldn’t might spreading the wealth. In today’s corporate sports-marketing world, it’s the equivalent of asking “Do you want fries with that?”

Savvy Knick fans may have already noticed the plan in action. Others will. Many of the 16,000 subscribers to the new NYK e-mail service have gotten messages offering discounts to St. John’s basketball games and the upcoming Oscar de La Hoya boxing match, for example.

It’s all part of corporate synergy, spreading the excess Knick energy into other events.

“Being a part of the Cablevision family, I have to use the power of the Knick name to promote other Cablevision properties,” said Mills, sitting in one of those $1,500-a-game courtside seats before a recent game.

Which is why some portions of Knick games seem like long blocks of commercials all wrapped up to look like public-service reminders. Got a back ache? Check out the Continuum Health Services desk at Gate 62, goes one such promo.

It’s the job of Mills, who looks much younger than his 41 years, to make sure those marketing efforts don’t snuff out the enjoyment factor of attending the games. So far, so good, Mills reports.

Mills also is busy in more traditional marketing endeavors, in what could be called the farm system of the team’s fan-mania, visiting schools with a Knick player, in hopes of turning those young fans into cash-spending faniacs.

Which can be hard, he said, when 80 percent of your fans will never see a game in person because of the scarcity of tickets.

“But once the kids meet a player, even if they can’t get to a game, they’ll watch him on television or buy a T-shirt or other product,” Mills said. “Or maybe they’ll go to the circus at the Garden. We try to get them thinking that the Garden is a magical place.”

Standing at the end of the tunnel now, halfway between the Knick dressing room and the court, Mills is in his element. He is also responsible for game day operations. Spike Lee, one of the Knicks’ courtside celebrity regulars, ambles out of the tunnel and greets Mills on his way to his seat.

Celebrities at courtside, a winning team, fan-based entertainment during the game and the marketing of the Garden as a special place is all a part of the buzz that keeps fans packing the place, Mills notes.

That buzz is needed when fans are paying an average $87 a ticket, the highest such price in sports, and the cheapest ticket in the house is $22.

Mills is always looking for ways to pump up that buzz, like adding new technologies to the player-introduction production and keeping those on-court fan challenges coming.

“Fans like those hokey entertainment pieces like fans shooting foul shots for prizes and kids running the length of the court wearing adult uniforms and adult sneakers and then shooting a layup,” Mills said.