The Super Bowl has become another national holiday designed to eat too much and watch football on TV. Except -- unlike Thanksgiving -- we get to spend this holiday with friends instead of family, and no one gets upset.

But why do we all watch this game?

In a culture that is becoming increasingly segmented and polarized by issues like politics and religion, I contend that we all still crave shared experiences that can unify us. While the internet can obviously connect us virtually to the larger world, the world wide web has also been the biggest facilitator of this fragmentation of interests and beliefs. And even as marketers continue to question the relevance of TV and even insist on its demise, TV continues to be the means to provide these rare shared experiences.

Unfortunately, though, many of these rare moments are often observed in times of tragedy. Think back to the tragic events of September 11, 2001, when we all witnessed the live horror together. That shared experience created an indelible mark on all of us, giving us a common understanding. And, even while the vast majority of Americans may not have been directly affected, that shared, visceral experience pulled us closer together.

The Super Bowl on broadcast TV gives us an opportunity for a shared celebratory experience, from the competition, to the half-time entertainment, to yes, the ads.

This Sunday night, almost half the country will watch the Super Bowl. And, because of the rarity of such a huge audience, $5 million for each 30-second slot is actually a fairly reasonable price to pay. On a cost-per-thousand basis, it's no more expensive than some of the best-rated, blockbuster prime time shows. And, appearing in the game provides the mantle of "Super Bowl ad," which means the brand will be talked about on websites, blogs and TV shows well before and after the game.

With the continuing fragmentation of broadcast stations, cable programming and satellite delivery, from a business standpoint, a single event generating such a large audience is very rare and very attractive. But not just to advertisers. It's attractive to all of us. If we believe others are watching, we want to watch, too. We don't want to be left out.

But, I would suggest that the greatest value comes in having your brand as part of this rare, unique shared experience. Knowing that others are seeing the ad at the same time we are creates a kind of imprint, a bond between all of us who watch. Many of us remember seeing Bird and Jordan playing HORSE for McDonalds, hearing "Wassup!" for the first time, enjoying Cindy Crawford enjoying a Pepsi and watching Chrysler reveal itself as "an import."

But, it may not have been the creative message alone that made an impression on us. The most compelling part of the experience may have been that we knew that everyone else was seeing it, too -- and we couldn't wait to talk about it the next day.

That's pretty comforting to all of us. And it's why we watch.