In the final weeks of December, advertisers distributed colorful circulars through newspapers or catalogs in the mail promoting holiday shopping specials. Every day, printed advertising material is delivered to homes. Some of it is welcome and used in finding bargains. Some of it unwelcome and goes into the trash. But all of it is has been paid for. Advertisers had to pay to have the promotional material printed and delivered.

In the digital world, e-mail promoting holiday shopping deals is delivered to e-mail in-boxes for free. In the days leading up to Christmas, major retailers bombarded e-mail in boxes with shopping promotions and deals for free shipping. As with printed material, some of these were welcome, but most were moved into the computer’s trash folder. Unlike the printed material that required retailers to pay for printing and delivery, it cost retailers nothing, or essentially nothing, to send these e-mails. Yet the people receiving the generally unwanted e-mail promotions paid a price in terms of the time to look at and delete the unwanted e-messages or spam.

Spam or true junk e-mails cost the U.S. economy billions of dollars in wasted time spent deleting. In the case of malware of computer viruses, a crashed hard drive or destructive computer virus can drive the cost much higher. A majority of all but the smallest companies spend anywhere from thousands of dollars to millions of dollars every year trying to manage junk mail, as well as protect their computer systems against computer viruses and malware.

One possible solution, at least for reducing unwanted e-mails like span, is a small, fraction-of-a-cent tax on e-mails, collected by Internet service providers. The idea is that such a small tax would have no impact on the average user sending 100 or so e-mails a month. The larger retailers and others who send out millions of e-mails a year would start to pay something for that service.

The more important consequence of a small tax on e-mails is that it might stop some spammers, who can send out millions of junk e-mail messages a day. The spam is maddeningly familiar, promoting cheap Viagra, weight loss miracles, bedroom performance enhancers, cheap printer ink and millions of dollars for helping heirs of a Nigerian prince trying to get a fortune out of the country.

Experts estimate that spam and other unwanted e-mails represents about 80 percent of all e-mail traffic on the Internet. In the first quarter of 2010, it was estimated that 180 billion spam e-mails were sent every day.

The cost to society, to individuals, to companies and unwitting victims of scam e-mail offers is massive. The cost for the mass e-mailers is next to nothing. If the spammers were forced to pay a fraction of a cent per e-mail, they might find it no longer made economic sense to send out millions of unwanted e-mails day.

The Internet and e-mail have changed the way the world works and have brought many efficiencies to our daily lives. But spammers sending millions of unwanted e-mails a day abuse the system. If one person out of million responds to their ads, they make money. For print ads, that kind of math does not work.

Spammers abuse the system and inundate our in-boxes because it costs them nothing to do it. It’s time for that to change.