Super Bowl advertising has crossed a threshold that's mind-boggling.

Would you believe $100,000 a second for a commercial during Fox's telecast on Feb. 3?

That's not $100,000 per commercial, that's $100,000 per second of a 30-second spot. That's right, some advertisers are paying $3 million for half a minute.

Not all advertisers are shelling out quite that much. The average price for 30 seconds of advertising time this year is $2.7 million, up from $2.6 million the year before.

So some advertisers are getting bargain-basement rates of $2.4 million. They're only shelling out $72,000 per second.

There are several reasons that Super Bowl spots continue to rise in value even as the nation's economy isn't looking so healthy, including:

• The ratings, of course. No other single broadcast in the course of a year draws viewers the way the Super Bowl does.

Last year's game averaged more than 93.1 million viewers. It was the third-most-watched single telecast in TV history, trailing only the 1983 finale of "M*A*S*H" and the 1996 Super Bowl.

The eight most-watched telecasts of any kind since 2000 have all been Super Bowls. There have, of course, been only eight Super Bowls since 2000.

And that 93.1 million number is an average. During the course of the telecast, more than 140 million Americans tuned in.

• The Super Bowl is our one remaining shared experience in TV. What with the proliferation of cable and broadcast channels, DVD, downloads and video games, nothing brings the nation together in front of our TV sets in such huge numbers, with the exception of the Super Bowl.

And, by the way, that includes the World Series, the NBA Finals, the BCS, even the Olympics.

• The Super Bowl is the one TV telecast in which viewers actually look forward to the commercials. Heck, there's research out there that indicates that some people tune in specifically to watch the commercials.

One survey found that 16 percent of Super Bowl viewers said they pay more attention to the advertisements than they do to the game.

That's not just gold to advertisers, it's gold, silver, diamonds, platinum ...

• The ongoing Hollywood writers' strike is helping to push up prices for Super Bowl advertising and sports-on-TV advertising in general. As the networks run out of original episodes of hit TV series, advertisers can either buy time on repeats, unproven replacement shows or sporting events ... and they're starting to choose sporting events more often.

In addition to the NFL's big game, TV networks report record numbers of advertisers looking to buy spots in the NFL playoffs, college football bowl games, college basketball, auto racing and even the upcoming major-league baseball season.

For years, the broadcast networks have looked to sports as "loss leaders" — they pay so much for the rights to the big franchises that they're lucky to break even. But even if they lose money, the thinking is that it helps drive viewers to other network programming.

Other network programming the networks are running out of.

But if advertising prices continue to rise, loss leaders might become profit centers.

Fox has reportedly sold about 90 percent of its advertising inventory for the upcoming Super Bowl. Which means if you've got an extra $3 million in your budget, you've still got time to pick up a 30-second spot.