Small businesses are indeed the latest target for spammers. Most small businesses -- unlike their big business counterparts -- have less sophisticated anti-spam protection, and spammers have shifted their tactics to take advantage of an easier target.

Unwanted email is a threat to both productivity and security. Spam now comprises more than 50 percent of all enterprise email and represents somewhere between 40 and 70 percent of all Internet traffic. Some data show that more than 30 percent of spam is generated by virus-infected computers, and more than 30 percent of viruses are propagated by spam.

The increasing interconnectedness of big businesses with small businesses, which are employing at best basic desktop antivirus defenses and very little spam protection, means that a large percentage of spam, virus, and blended attacks are spawned small businesses.