Your List Is in Danger of Being Poisoned

Nov 21, 2006 9:50 PM  By

(Magilla Marketing) Your marketing efforts could be 100% opt-in and your outbound e-mail could still end up being blocked as spam. The problem: list poisoning.

It has been happening for years but many marketers who use e-mail are unaware of it, according to George Bilbrey, vice president/general manager of Return Path’s Delivery Assurance division.

To poison a marketer’s list, someone—possibly a competitor, or just someone with too much time on his hands—writes a small computer program that dumps a bunch of bad addresses into a company’s sign-up form and hits the submit button.

List poisoning can result in a marketer’s outbound e-mail being labeled as spam and blocked by inbox providers even for marketers who collect addresses on an opt-in basis. It is the second-most common cause of an opt-in marketer’s e-mail getting blocked, Bilbrey says. The first is using a sloppy third-party data source, he said.

List poisoning “doesn’t happen every day, but when it does, it’s a problem,” says Bilbrey.

And forget about trying to catch whoever poisoned the list, he adds. The trick is to protect against them before they strike.

One way to protect against list poisoning is by using so-called closed-loop permission practices when collecting e-mail addresses, says Bilbrey. Closed loop—also known as double opt-in—is where the person who signs up for a marketer’s e-mail gets a confirmation message to which he or she must respond in order to remain on the list. The tactic prevents list poisoning by requiring a human to verify the request.

Some marketers balk at using double opt-in, however, contending that the process creates too many annoying steps for registrants who have already said they want what the marketer has to offer.

For those who aren’t using double-opt-in, Bilbrey recommends quarantining newly collected addresses.

“Then you monitor those very closely to see if they’re hitting spam traps,” he said. Also, if a lot of requests come from the same IP address over a short period of time, it is a good idea to flag those addresses as possible attempts at list poisoning, he said.