Any discussion of spam-sensitive industries needs to include ISPs.Any discussion of\u00a0spam-sensitive industries needs to include ISPs. ISPs spend a fortune trying to reduce the quantities of junk mail sent to - and by - their subscribers. ISPs formed the Anti-Spam Technical Alliance expressly for that purpose. The alliance has taken measures such as targeting "zombie" PCs that are used to launch mass mailings without their owners' knowledge.Despite efforts on the legislative and technical fronts, only the most optimistic ISPs hope for decisive victory over spammers in the foreseeable future. So they've learned to savor the temporary triumphs, short-lived though they might be.Cable television provider and ISP Charter Communications recently earned one of these short-term breathers. Charter, of St. Louis, switched to an anti-spam approach that uses Symantec's Brightmail for content filtering and IronPort Systems software for network monitoring."Those are our two new weapons," says Laurie Jill Wood, director of Internet security at Charter. In the first 24 hours of the Brightmail\/IronPort use, the company blocked 31 million spams from customer mailboxes, according to Bob Bosco, director of Charter's mail and Web complex. (The company has 1.8 million subscribers.) Many customers immediately noticed and commented on the spam reduction, she adds."Charter understands that blocking spam is an ongoing effort. Hopefully, we can keep ahead of the game," Wood says. Back to feature: "Word up"