Check out this very informative new article from ClickZ. Here's an excerpt:

When spam makes its way into the inbox of a business account, it can sap an employee's time as they filter out unwanted messages. A recent survey finds employees spend as much as one hour per day deleting spam. That's 12.5 percent of lost time for a staffer who works 1,824 hours per year.

The survey also identifies the perils of false positives which include job termination, broken relationships, missed flights and other embarrassing situations.

While spam often transmits malicious code through attachments or by tricking recipients to visit a site to infect computers, several security firms have identified a worm that infects computers when the e-mail is opened in Yahoo Mail.

One in every 141 e-mails is virus infected, down from one in every 38 e-mails counted in May of last year. "The proportion of virus infected e-mail has dropped considerably over the last year as hackers have turned from mass-mailing attacks to targeted Trojan horses," said a statement issued by the company.

Read the whole article here.