Email Verification & Marketing

Get on Mailbox Providers’ Nice List this Holiday Season

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Over time, some things change and some do not—like spam. Recent stats show spammers were the first movers in adapting to the pandemic and being innovative getting past spam filters. While marketers were busy strategizing to update their outreach to customers, spammers found ways to keep spam filters over-worked and on their toes. As the holidays approach, the collateral damage of deeply disrupted email marketing activity is legitimate senders finding themselves unprepared for the season.

Having spent few holidays fighting spam in the trenches, it will be interesting to see how this year plays out for senders and receivers. We are amidst a pandemic and our usual strategies around holiday sending need to be tweaked. Holiday email or not, email marketers need to incorporate into their sending strategies how receivers will view and action our mail. Filters have definitely evolved, but there are few basics to keep in mind as we approach the holidays.

It’s all about mail volume.

Each year during this time, every legit mailer on the planet looks like a spammer to the filters due to their mail volumes. Year-over-year reports show mail volume during peak holiday season has exponentially increased. Every brand wants the top real estate in your mailbox, but so do spammers trying to find new techniques to sneak in all that mail via legitimate sources. (Did you know most spam is sent from the top three webmail providers?)

Infrastructure has a cost connected to it, and there is only so much mail a receiver can accept during this time. Most spam filters do not make any new changes to their algorithm during the holiday season, so don’t expect them to adapt to your new sending behavior or practices. The global rule sets (Gateway filter or blocklists) at spam filters take charge more than the user-level filters to fight spikes in mail volumes. Would every sender be throttled if they are sending high volume of mail? No, you could get that prime real estate if you have maintained a consistent mailing volume and organically grown a list with good levels of engagement with your mail leading to the holiday season. But this is not the time to re-engage your customers or introduce a high volume of new subscribers in hopes engagement levels will catch up.

Throttling: 421 is the new 554.

Since the early part of the decade when IPv6 was supposed to take over the internet, most receivers warmed up to the idea of moving away from relying only on IP reputation. This was accelerated when receivers realized their trusted sources were where most spammers migrated (remember how I said the top three webmail providers send the most spam?). Spammers evolved, making it essential for filters to evolve, too.

Domain reputation has taken precedence, and most filters at major webmail providers are robust enough to make decisions based on multiple factors other than IP reputation. From a receiver’s perspective, it is as important for spam to be spam-foldered as it is legit mail never going to the spam folder or getting blocked. Cheaper storage and smarter AI modelling algorithms have helped receivers place more mail into a mailbox rather than outright blocking it (and rely less on IP-based blocklists). They would rather spam-folder an email about which they are unsure and let the user decide if the mail is ham or spam. This results in filters giving lower 554 rejects and more 421 temporary errors. It is lighter from a data storage perspective to spam-folder email with neutral reputations than placing them in the inbox (mail in the spam folder auto-expire).

A high volume of email being spam-foldered is an early warning signal of reputation issues at a receiver: This is where a solution like Validity for Email will help you. The holiday season is the most important time to be on high alert for these. Any spike in mail volume causes 421 delays and eventual permanent failures. Temporary failures are the best defense mechanism for filters to fight mounting volumes. Monitor bounce logs for deferrals—some email service providers (ESPs) provide this info, and a solution like Validity for Email certainly gets you that visibility. Then, ask your ESP to either slow down, or make changes to your volume to cut back to sending to recipients based on their engagement.

Domain reputation is the secret sauce.

When you know our sending volume is going to increase, it is imperative you get the best practices right. This starts with authentication. Since all major webmail providers moved to rely on domain reputation, ensuring you brand your mail with custom DKIM domain signature has important benefits. An authenticated email with a branded domain helps build your reputation sooner and improves the overall trustworthiness of an email. This along with ensuring the URLs in the content of the email are branded to either your own domain or your ESP would rule out any domain reputation spillover effects. Along with DKIM branding, segregate your mailing via sub-domains. You can afford to have a few of your promotional mails throttled, but not your transactional mail.

The bottom line is receivers are ready to protect their users, not email marketers. You’ll need to put yourself in their shoes to understand the best practices you can’t skimp on to ensure you’re going to be placed in the right spot, not spam-foldered or blocked entirely. What makes this even trickier is not only do you have to balance the needs of the technical mail receivers, but the needs of your subscribers. We’ll get into that later this week. For now, I hope you have a better understanding of what you need to do for mailbox providers, but if you need more help, just drop us a line.