Spam is hitting the big time and will make up half of all corporate e-mail in 2003, the Aberdeen Group predicts. As with all industries, there\u2019s a division of labor. Each of those annoying, unread lines in your inbox is really the last step in a sophisticated supply chain?or rather the next-to-last step. "Somebody must be buying the stuff, or none of this would be profitable," says Maurene Caplan Grey, a research director for Gartner Research. Grey breaks down the spam supply chain this way: Software providers The people who create software that makes it extremely easy to send blanket e-mails?to johna, johnb, firstname.lastname@example.org?that look for valid e-mail addresses.E-mail harvesters: The people who spend all day using this software to hunt for valid e-mail addresses, which they compile into lists and sell. Pay dirt? An autoreply set up by someone going on vacation.Spammers: The people who actually send out the mailings?again, using specialized software?that promise fame, fortune and enhancements for body parts that recipients might or might not have.Sellers: The companies looking to hawk their goods or services to anyone@anywhere.Profit-seekers are also on the other side, of course. Just ask Network Associates, which in January bought Deersoft, a San Mateo, Calif.-based provider of antispam technology, for an undisclosed amount. Art Matin, president of Network Associates\u2019 McAfee unit, says the acquisition is just "the first in a series of investments" in antispam and content-filtering technology.