Adam Penenberg: Sure, some think that publishers who demand registration for news are a pain in the digits, or that sites which don’t accept alternative browsers are sacrilegious. And of course, the unrelenting stream of porn and other nasties is a major turnoff. Still, they don’t come close to making people’s blood boil like junk e-mail and “pops” do.

That being the case, you might think they couldn’t possibly work. But if you did, you’d be wrong. On the contrary, they are enormously successful.

Quite a surprise, since here I was believing that spam existed merely to give my fingers an aerobic workout from pounding the Delete key. As for pop-ups, I thought their primary function was to entice me to switch to Mozilla, a browser that suppresses them, or to download pop-up ad-buster software.

But in the online marketing game, I learned there are a number of popular misconceptions floating around.

Myth: Spam can’t possibly work because no one is stupid enough to fall for come-ons for penile enhancements, lower mortgage rates and Nigerian scams.

Fact: If only that were true. “Spam does work, but in a relatively artless way,” said David Schwartz, a director of sales at Claria, an online behavioral marketing firm. Since there is almost no cost associated with sending out millions of e-mails (unlike, say, with mail-order catalogs that require hefty postage), spammers require a miniscule click-through percentage.

In the mail-order business, you’re lucky if 2 percent of the people who receive your catalog actually buy something. But if a bulk e-mailer sends out 1 million messages for a product that he sells for $20, he only needs 0.1 percent to purchase it to earn $20,000. Multiply that by the number of bulk e-mailers and it’s no wonder a study by the Direct Marketing Association found that consumers spent $32 billion on products and services advertised in e-mail in 2003.

More here.