I’m often reading emails from customers asking the same question: Why can you get my email to the inbox when I keep sending it to Spam. Well...because we’ve paid off the ISPs and they let us get right through (not, we wish). The true answer is complicated, but I’ll try to explain the various moving pieces here.
IP Reputations #
For those familiar with bulk email, you know that your IP reputation is a crucial part of getting to the Inbox. Over the last 6 years of running Newsberry we’ve learned and watched the industry evolve in this area. Today, ISPs spend a large part of their energy trying to fight spam, so they put the burden of proof on the sender. Your IP reputation depends on many factors, including:
- Spam complaints
- Bounce/unknown sender rates
- Spam trap hits
- Content type (transactional, bulk, etc)
- Engagement (a still to be determined measure, including open rates, click- throughs, forwards, etc)
Before you can even build a reputation, you need a significant volume of emails, so there is enough data to build upon. Once you start sending a lot, then you need to make sure you are sending to people who expect the email. If they expect it, they will open it and read it (engagement), and they won’t click Spam (usually). Here at Postmark, our IP reputations are exceptional, getting to the Inbox 98-100% of the time. We use an external service called Return Path to monitor our delivery rates.
Back-end Infrastructure #
Another important part of sending successfully is setting up your mail server properly. This includes what we call ‘being nice to the ISPs’. All of the ISPs you send to have requirements for the number of open connections you should send at any given time, and then how many emails you should send in each connection. They go further to dictate what you should do if they send certain responses back (stop accepting connections). We use a super powerful mail server from Port25. They allow us to set these thresholds for each ISP individually, and then we make tweaks and changes instantly. If we send too many connections, or don’t backoff when they ask us to, they will bulk our emails, or worse, just discard (read: email disappears into nowhere).
Whitelisting, feedback loops and bounce handling #
A part of being nice to the ISPs is setting up a relationship with them. Some ISPs allow you to whitelist your IPs and/or domains with them so their spam filters act friendlier when they get your email. While whitelisting isn’t as popular as it once was, it does still help for several large ISPs.
We have also setup feedback loops with all the ISPs that provide them, so we get instant information on subscribers who click spam. This way, we can immediately notify you and stop sending to those people. This is mission critical to prevent delivery problems. If someone clicks spam, do not send to them again! They will click spam continuously if they keep receiving your email.
Similarly, removing unknown email addresses right away is important to keep your bounce rates low. A lot of web apps who send on their own SMTP don’t have any bounce handling and continue to send to the same nonexistent address. This tells the ISP you aren’t keeping your list clean, and they will start to react negatively towards you.
Your responsibility #
We do everything we can to give you a direct connection to the Inbox, but much of that success still depends on you. In addition to the items mentioned above like spam complaints and permission, content is important. This, in my opinion, is one of the most difficult parts of email sending, because it is subjective. We can have everything above in place, but if your email says “Free Viagra” you will get blocked. And I know this is an obvious example, there are many other not so obvious content flags that can get you blocked. I always recommend to our Newsberry customers when they have content issues to take a tour of their Spam folder. Don’t do what they do. Some examples:
- “Free” is not a good word for an email
- ALL CAPS is something spammers do to catch your attention, especially in the subject line
- Large images with little text get flagged and often delay sending
- Exclamation marks do not belong in the subject line, either
These are just common issues I see, a lot of times it’s much more complex. My suggestion is to provide the important information, in a clear, concise manner. If you start seeing bulking, start with exploring your content as well as the IP and service provider.
If you have questions about content, feel free to email us. We’re always happy to look at your email and offer suggestions.
This post was originally published Jun 10, 2010