With more than 27 million golfers in the United States alone, golfing for business purposes is a great opportunity. Whether you're opening doors or closing deals, golf can enhance almost any business relationship.

Golf is a networking game par excellence. In what other environment can you see your customer for four to five hours interruption-free?

In the United States, an estimated $28 billion in annual sales is attributed to contracts and relationships initiated on golf courses. That's why more than 20 million rounds of business golf will be played this year.

And women are taking up the game in droves. More than 25 percent of the golfers in this country are women, up significantly since the early 1990s.

"Women are seeing golf as an informal network to advance their careers," said Carol Bresnicky, representative for the Executive Women's Golf Association, whose membership has soared to 20,000, from 1,500 in 1991.

A survey of corporate meeting planners by a trade magazine found that golf was more important to attendees than a beach, a spa, shopping, cultural attractions or other outdoor sports.

It's also important to note that golf tends to expose your true character. In one study, 47 percent of those surveyed believed that behavior on the course usually paralleled behavior in business.

It tests your fortitude, your confidence and your humility. If you're making a key hire or closing a business deal, golf can show you how people act in all kinds of circumstances. You can take note of their appearances, how they carry themselves and how well they follow the etiquette and rules of the game -- even if they know how to have fun. And remember: They can see how you handle yourself as well!

It's equally important to follow golf and have an interest in the sport. After all, you can't talk about business all the time, so golf is a great icebreaker.

If you want to move up in some companies, it doesn't hurt to hang a golf picture or have a putter and some golf balls in your office. It helps build rapport and relationships, and it's a great -- and safe -- topic of conversation.

So why is golf so popular? A friend shared an e-mail that seems to be a compilation of anonymous sources:

• Golf is an honorable game with the overwhelming majority of players being honorable people who don't need referees.

• Professional golfers are paid in direct proportion to how well they play.

• Golfers don't hold out for more money or demand new contracts because of another player's deal.

• When golfers make a mistake, no one is there to cover for them.

• Golf doesn't change its rules to attract fans, and golfers have to adapt to an entirely new playing area each week.

Mackay's Moral: Any way you slice it, golf suits business to a tee. Get out there and have a ball.