5 Things Marketers Should Know About Spam Filters

Sometimes context means everything. Especially when an e-mail contains "XXX." So while Super Bowl fans may have found messages from the National Football League innocuous, spam filters did not. The filters didn't bother to understand the concept of Roman numerals that counted out the games between 30 and 39. So e-mail experts did, and here they provide more tips for marketers in similar fixes.

"As you might imagine, 'XXX' lights up like a Christmas tree," says Rick Buck, director of e-media and privacy/ISP relations for e-mail service provider e-Dialog, headquartered in Lexington, Mass. "Back in the early days, when spam filters were just coming into the horizon, that became a real problem for [the NFL]. But the good news was the spam filters pointed it out ... [and] we were able to figure out ways to optimize the creative in such a way that [the] image could be shown without showing up as something that would be blocked by spam filters."

While some marketers may believe those bad old days are gone, those who work in the e-mail space say that's both true and false. Content filtering is back, they say, and is included in the important knowledge marketers should have about spam blocking systems.

1. The filters need to see a valid domain key so they know the e-mail's return path is real. "First thing [spam filters will] do is take a look at your sender address, and they'll take a look to see if there are e-mail header technologies involved, such as DKIM and SPF," says Aaron Smith, a principal with Seattle-based e-mail marketing strategy and creative services agency Smith-Harmon. "These authentication mechanisms serve as a sort of handshake so that the server can actually go to a very specific location and say, 'Oh, OK, yes. This really is a server.'"

2. Do a good job of managing sending IPs in order to maintain a good reputation. Relationships with spam filters do matter to a sender's reputation, but spam filters factor in that reputation, too, Buck says. So to stop that never-ending circle from spinning, he recommends that marketers also pay attention to list hygiene, bounce rates and complaints. "If you're focused on doing all of the right things in the first place ... you almost won't have to worry about [the spam filters]," he says. "Because you're going to have a great reputation, because you're going to minimize your bounces, and complaints and minimizing your bounces and complaints, frankly, keeps your IP reputation up. If your IP reputation stays up, that's also part and parcel because your creative is good, because your copy is good, because your audience is good, because your message is good."

• MORE ON
• ONLINE MARKETING