What does good IP Reputation get you?

laura
Industry
March 8, 2018

Today I was discussing some mailing list posts with an ESP colleague. He was telling me some interesting numbers he’d collected from different IP pools they maintain. He was testing routing mail through IPs based on subscription process and routing based on engagement metrics. The data showed that inboxing rates were similar across the test groups. As he put it, “IP reputation didn’t have much impact on inbox delivery.”

I’m not surprised. I’ve been talking for a while about how IP reputation is less important in reaching the inbox. In fact, it was almost 5 years ago now that I wrote The Death of IP Based Reputation. I updated it in 2015 with Deliverability and IP Reputation. Overall, IP reputation is a much smaller piece of reaching the inbox now than it has been in the past. I’ve talked about the reasons for this in the above posts. The short version is:

IP reputation is a crude hammer;
IPv4 addresses are in very limited supply, in network terms more customers / IP is a good thing;
Spammers use botnets, sending large amounts of email across many IPs;
IPv6 is huge and IP based blocking will be challenging and of limited effectiveness; and
Better computing power makes content scanning more feasible.

IP Reputation Still Matters, a little

This doesn’t mean senders can, or should ignore IP reputation. Even Gmail looks at IP reputation a little bit. The place IP reputation is primarily used during the SMTP transaction. Good IP reputation does lead to less rate limiting. Senders with good IP reputation can send more mail faster than senders with poor reputation. But once the SMTP transaction is over, IP reputation is just a small factor in a large pool of variables.

IP Reputation Still Matters, a little more.

There are some places that heavily rely on IP filters. And some places that rely on certain types of IP filters. Most of the major providers will block mail from home users, dynamic IPs, and infected machines. Additionally, there is and will probably always be a long tail of domains that are still relying on IP based filters. It’s a crude hammer, but it’s an effective one. Typically, though, IP reputation in those cases is in the eye of the root user. The good news is, these are often private networks, and users have the option to use less restrictive free providers if they’re not getting the email they want.

IP reputation and email delivery

IP reputation is a measure of how much wanted mail a particular IP address sends. This wanted mail is measured as a portion of the total email sent from that IP. Initially IP reputation was really the be all and end all of reputation, there was no real good way to authenticate a domain or a from address. Many ISPs built complex IP reputation models to evaluate mail based on the IP that sent the mail.
These IP reputation models were the best we had, but there were a lot of ways for spammers to game the system. Some spammers would create lots of accounts at ISPs and use them to open and interact with mail. Other spammers would trickle their mail out over hundreds or thousands of IPs in the hopes of diluting the badness enough to get to the inbox. Through it all they kept trying to get mail out through reputable ESPs, either by posing as legitimate customers or compromising servers.
These things worked for a while, but the ISPs started looking harder at the recipient pool in order to figure out if the interactions were real or not. They started looking at the total amount of identical mail coming from multiple IP addresses. The ISPs couldn’t rely on IP reputation so they started to dig down and get into content based filtering.
As the ISPs got better at identifying content and filtering on factors other than source IP, the importance of the IP address on inbox delivery changed. No longer was it good enough to have a high reputation IP sending mail.
These days your IP reputation dictates how fast you can send mail to a particular ISP. But a high reputation IP isn’t sufficient to get all the mail in the inbox. It’s really content that drives the inbox / bulk folder decisions these days.

Generally IPs that the ISP has not seen email traffic from before start out with a slight negative reputation. This is because most new IPs are actually infected machines. The negative reputation translates to rate limiting. The rate limiting minimizes people getting spam while the ISP works out if this is a real sender or a spammer.
Some ISPs put mail in the inbox and bulk foldering during the whitelisting process. In this case what they’re doing is seeing if your recipients care enough about your mail to look for it in the bulk folder. If they do, and they mark the mail as “not spam” then this feeds back to the sender reputation and the IP reputation.
If you’re seeing a lot of bulk foldering of mail, it’s unlikely there’s anything IP reputation based to do. Instead of worrying about IP reputation, focus instead on the content of the mail and see what you may need to do to improve the reputation of the domains and URLs (or landing pages) in the emails.

Delivery and marketing part 2

A while ago I wrote some thoughts about the conflicting requirements of delivery and marketing. I posted something similar over on the Only Influencers list, too. My thoughts generated a very interesting discussion, one that helped me clarify some of my somewhat random thoughts from earlier.
Marketing is about finding mindshare. One way you get mindshare is repetition. But people tune out repetition pretty quickly. Sending the same offers, the same copy over and over again means recipients start to tune things out. When recipients start tuning out mail, they may not bother opening it, they just read the subject line. If too many recipients start relying on the subject line then delivery can suffer.
Effective marketing relies on getting mail in front of the target audience. That’s the delivery component. Without inbox delivery, even the best marketing will not work.
No one will see marketing if it is in the spamfolder.
I don’t think you can cleanly separate delivery strategy from marketing strategy, but it’s important to realize they have different constraints and different pressures. When I talk about delivery with a client, I’m talking about getting mail into the inbox. And, most of the time, they’ve come to me because they’re not getting into the inbox and they have to make changes. The genius of their marketing is irrelevant, because no customers see it.
But once mail is in the inbox you can’t just ignore delivery, either. Sure, it becomes less of a pressure on the copy and the marketing strategy, until such time as the mail isn’t getting into the inbox any longer. Then it’s back to working on delivery and maybe having to implement some aggressive data hygiene. Back in the inbox and you can be aggressive on the marketing again.
Successful email marketing requires balancing the constraints of good delivery against the constraints of good marketing.

ISPs speak at the EEC conference

Massimo Arrigoni has a great blog post up summarizing the final session of the EEC conference with representatives from major mailbox providers. This session a number of representatives from major mailbox providers spoke about what it takes to get to the inbox. They discussed what engagement really was, why you need to warmup and what the mailbox providers are measuring.
The short version is delivery is becoming more and more personalized. It’s not about if a mailbox provider thinks mail is spam, it’s about if a mailbox provider thinks this recipient thinks the mail will be spam. It’s all about connecting with each individual recipient.
None of this should be news to any of our regular readers. We’ve long talked about how ISPs measure things differently than senders. We’ve also talked about personalized delivery and how IP reputation isn’t the most important part of delivery.
Know your recipients. Make them want your mail and it will end up in the inbox. ‘
Edit: EmailCopilot also has more information on the ISP session at EEC.