In case you missed it, our Delivery Consulting Team hosted an hour-long Q&A webcast last month on all things delivery. The team answered a slew of questions ranging from Gmail’s promotions tab, to email metrics to watch, to what DMARC really stands for and which policy to implement.

Below, our delivery experts will share details on two topics that came up during the webcast: spam filters and throttling.

How do I avoid spam filters?

Kurt: First, send wanted mail. Make sure you’re paying attention to your users. If you see users stop engaging, you need to stop sending to them. The messages that are turning off those users who aren’t engaging are going to drive down your overall inbox placement.

Second, Internet Service Providers (ISPs) look at engagement to determine your reputation. If a recipient stops engaging, that’s going to lower your reputation and more of your messages will go to the spam folder. So paying attention to user engagement is key. But also keep in mind, all the ISPs are different. What works for Gmail is not going to work for Yahoo. They have different expectations of what an engaged user is.

Lastly, consider slowing down your frequency. Send to less engaged users once a week instead of every day, and then maybe once a month if they trail off. Then try to incentivize them to bring them back onto your list.

How do I know if my emails are being sent to spam?

Kurt: There are actually two ways you can tell.

First, we subscribe to a third party software that tells us where your messages are landing. Is the ISP filtering a message automatically to the spam folder, or is it going into the inbox? So we (the consulting team) do have some insight into that. But unfortunately, the ISP response code that we get, regardless of where the message went, is a 250 OK which means that the ISP accepted the message.

The second way to tell is if you have a high delivery rate, but your open rates are really low at one particular ISP. For example, at Gmail, your open rate could be only 1%, but at Hotmail it’s 20%. Gmail’s accepting the messages, but they’re filtering to the spam folder.

Jacob: As Kurt had mentioned, looking at an increase or decrease in opens and clicks is a great thing to monitor. Though there are some general aggregate stats to look at to measure yourself against other senders in your industry, you really need to focus on yourself. If you have always been successful at a certain open rate and then now it’s lower, then it’s the time to look into it. So really compare yourself to your own business when things were working properly. That’s a better litmus test.

What do you recommend for timing/pacing when sending large amounts of email? Experience tells me that if I send too many it can put my campaign into quarantine.

Luke: Sometimes it’s worth considering timing and pacing. You should know when your recipients are most active or, if it’s a flash deal, whether it’s going to be more timely to send them out per time zone. Like spread them out across your three American time zones, then your European time zones like that. That totally makes sense. The number of emails is likely not what’s sending the messages into the spam folder, but how the mail is being responded to definitely can.

So if you send 300,000 emails and within the first half hour, you get let’s say 100 spam reports, that could be enough reports that if the mail hasn’t finished delivering, it could be enough to start some throttling. And if it was delivered, in the case of Microsoft, they can actually retroactively remove a message from the inbox and put it in the spam folder, but that will be based on how the users interact with the mail. But I don’t believe that it’s the volume itself that’s the issue.

Seth: I’d also say to you, segment that list. From that 300,000, I would start with my most engaged recipients first. The users who have opened in the past week would be the first part of the list that I would send to. And the last part would be people who have engaged within the last six months.

It helps ISPs when they see higher engagement with the initial part of the list (like Luke was mentioning). Once some of the mail is delivered and the ISPs see that you have high engagement up front (because you’re sending valuable content), they’ll continue accepting the mail for the rest of your list.

If you’re interested in listening to the entire Q&A webcast you can find it here and the Delivery Consulting Team consistently contributes articles to our blog, so be sure to check out the blog author profiles for Kurt, Luke, Jacob, and Seth.



Kate Schmeisser
When Kate isn't trying to teach herself the ukelele, make it through the mountain of books on her nightstand, or figure out if they are actually being serious about suggested serving sizes on ice cream, she is the Creative Content Manager.