By all accounts, spam is on the rise again. You can hear it in the numbers being quoted by the well-known anti-spam companies (they seem to agree that it has almost doubled over a year ago) and you can see it just by looking at your inbox. Spammers have found a few new tricks that have proven particularly successful at getting past even the most modern filter.

First, they are using very, very short text-based messages that make it nearly impossible for a computer-based filter to differentiate from a human-originated message. Second, they are using more image-based spam. Again, computers can't read images, and inbox providers are reluctant to start filtering images wholesale from email. Third, many of the spam emails are simply pump-and-dump stock messages that don't require any click-throughs to achieve their goals. Fourth, and most challenging of all, spammers have now enlisted tens of millions of zombie computers to send their messages. No longer can bad email be pinned to a few IP addresses. Instead, messages are coming from countless home and work-based computers that have been compromised by Trojan software and silently been put to use in a massive, distributed spam sending engine. You can read more about these issues in this blog post by MSNBC's Bob Sullivan.

While this resurgence of spam may seem like just a new round of annoying inbox clutter, it is possible that it will drive the next set of lock-downs from ISPs and even the government. While we need to get on top of the growing spam problem, it is possible that the next set of anti-spam moves may go beyond image-blocking and potentially could put a real dent in the email marketing business. I recommend we all keep our ears to the ground on this and work through organizations like the Email Sender and Provider Coalition to help find balanced solutions that stop spam, but allow businesses to continue to use the email medium for legitimate, permission-based communications.