Digital MarketingEmail MarketingHow Spam Complaints Affect Delivery

How Spam Complaints Affect Delivery

Every e-mail marketer receives spam complaints. Where complaints generate, how they're used, and what you can do to minimize them.

Every email marketer receives spam complaints. It doesn’t matter if you use confirmed opt-in or have never seen a complaint in your life. Your messages do get complaints. Unless you use an email service provider (ESP) or your ESP doesn’t provide these services, you might not have immediate access to these complaints.

Spam complaints are a useful metric for two reasons. First, they indicate how closely you follow best practices. Second, ISPs and anti-spam services use them to filter and even to block messages. Today, a look at where complaints generate, how they’re used, and what you can do to minimize them.

How Users Report Spam

There are three primary ways email recipients can file complaints:

  • Most large consumer ISPs include a link or button that allows recipients to flag spam messages:
    ISP Report Spam
    AOL Yes Yes
    Yahoo Yes No
    Hotmail Yes No
    EarthLink Yes No
    NetZero Yes Yes
    Juno Yes Yes
  • Recipients use a spam complaint service, such as SpamCop or Vipul’s Razor.
  • Recipients send complaints directly to email abuse addresses at ISPs and the FTC.

Monitor Spam Complaints

To ensure you see the complaints your messages may generate, follow these steps:

  • Make sure your “abuse@” and “postmaster@” addresses are valid and can receive email. Get access to those addresses and review the incoming mail. These addresses are recommended Internet standards set by the Internet Engineering Task Force (IETF) for complaint reporting.
  • Register the above addresses with It’s a clearinghouse for registered abuse addresses used by many network administrators and tools to route complaints to the proper destination.
  • Register for a feedback loop. See the table above for some ISPs offering feedback loops. AOL’s feedback loop, for example, is set up as part of its whitelisting process.
  • Provide complaint instructions in your privacy and anti-spam policies. Often, less tech-savvy recipients want to complain to you directly, but don’t know how. Link to your privacy policy from the email’s footer.

How ISPs Use Spam Complaints

ISPs use complaints for many reasons. Complaints contribute to ISPs’ content filters, especially the learning filters, to help improve their predictive algorithms. They also use complaints as a sort of voting system to deem whether email coming from a certain IP address is good or bad. Too many complaints may lead to a message being filtered into bulk folders or rejected entirely. ISPs may then require the sender take specific steps, such as reconfirming a mailing list, before allowing more traffic from the sender.

Spam complaint percentages (spam complaints divided by messages sent, multiplied by 100) can vary widely based on list composition, opt-in approach, content type, frequency, your brand, and more.

AOL recommends keeping spam complaints below 1-3 percent of traffic, depending on volume. This figure is unique to AOL’s user base; it’s too generous when applied as a general standard. Be at or below the range of one complaint per 6,000 to 8,000 messages, or 0.013 percent.

Minimize Complaints

Minimizing complaints always starts with practices used to collect email addresses. It should be obvious by now sending unsolicited email only gets you in trouble. Mailing lists with the lowest complaint rates are either confirmed opt-in or properly managed single opt-in. If you have a solid permission-based list but still find incoming complaints are higher than the optimal rate or are rising, consider the following:

  • Brand your subject lines. Mail systems with spam complaint buttons offer it at the inbox level. A recipient need only to scan subject lines and decide which messages not to delete immediately. A subject line such as “Exciting offers for you, Bob!” will surely be marked as spam. Consider using your company or newsletter name in brackets at the beginning of your subject lines.
  • Consider including unsubscribe instructions at the top of your email, in addition to the footer. Some users use the “report spam” button as an unsubscribe method and won’t scroll through an entire message to find that link.
  • Include instructions for users to whitelist your domain. This prevents a user-based filter from mistaking your message for spam and either diverting it to the spam folder or prefixing “[SPAM]” to the subject of the message.
  • Provide a preference update page. Disclose how your organization will use a subscriber’s email addresses, and how often. Allow subscribers to select preferences on the opt-in form, and link from email to a preference or profile update page.
  • Avoid spammy looking content. Try not to use garish, bold fonts; large, red letters, and the like. Avoid images with poor compression quality. A clean, readable design isn’t as likely to be mistaken for spam.
  • Don’t over email. If recipients expect to receive a few informational email messages each month from your company, don’t suddenly start sending two or three each week.
  • Don’t send unexpected email. If subscribers opted in to receive your “Trends & Tips” newsletter, don’t send them your hard-sell e-commerce messages, unless they clearly requested them.
  • Include opt-in information. If possible, add to your email admin area information, such as the subscriber’s email address, date of opt-in, and how she potentially subscribed (product registration, white paper download form, sweepstakes entry, etc). With many subscribers receiving dozens of commercial email messages daily, it’s easy to forget signing up for your newsletter — and then to file a complaint.

Spam complaints are an unavoidable and important aspect of email marketing that can’t be overlooked. In most cases, above-average complaint rates suggest poor email practices that over time lead to decreasing open and click-through rates. In the short term, too many spam complaints simply get your email filtered or blocked.

Till next month, keep on deliverin’.

Want more email marketing information? ClickZ E-Mail Reference is an archive of all our email columns, organized by topic.

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