How to help marketing emails avoid spam filters and reach your customers

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Aime Cox
Founder of Studio Cotton
Aime is utterly obsessed with sharing heaps of small business and website advice that’s easy to action
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This article and all others on the Studio Cotton blog are written by humans. Please enjoy our opinions, expertise, advice, experiences, and typos.

It’s time to buckle in for a hella dry blog post on some technical gubbins within email marketing. If that sentence bored you, it’s only gonna go downhill – so maybe come back with a G&T and I’ll be far more entertaining, promise. Here’s how to help your small business marketing emails avoid spam filters and reach your customers.


How to avoid spam filters is an answer too long for Instagram

Today’s blog post is a direct response to a comment I received on an old Instagram grid post:

“I have a little question regarding email marketing. Is there a way to make sure your clients are getting their emails? I ran an event and collected emails on paper and when I sent a follow up email, lots of people told me at a later date they never received it.

I’ve tested sending emails using the Bcc feature too and this seems to send it to people’s junk… Do I have to sign up to mail chimp or similar for it to be effective?”

I was chomping at the bit to answer this bad boy because, as those who know me well are aware, I think email marketing is the tits. In fact, pre-Studio Cotton, email marketing and customer relationship management (CRM) were my specialities.

Nowadays, I spend most of my time convincing small businesses to start investing in email marketing, explaining how to compose a compelling message, and begging very nice people to please, please, please stop dropping meandering essays into eager inboxes – but I rarely get technical. And I love getting technical, that’s my jaaaammmmmm.

This robot is full of ways to avoid spam filters
Getting technical with spam filters

I couldn’t not reply to this comment, but I also couldn’t reply on Instagram but this pish goes deep yo, and there’s only so much you can fit in a comment. I asked the Instagram user to pop me an email and I’d craft a full explanation. They did, I did, and then I asked if I could share this in my blog.

And here we are.


Big-ass caveat

If you’re an email marketing whizz reading this – hey babes, let’s talk click-to-open rates as a metric for content quality sometime. You’re also going to think “hey Aime, some of this isn’t 100% accurate to every scenario, or you’ve made a big ol’ generalisation”. Well babes, I have.

This lil article is aimed at small business owners who don’t need to know all the extra-dry secret stuff in our brains.


How a Hosts evaluate the spam-iness of an email

There are a few different factors that affect how likely it is that an email we send will end up being marked as spam. Each Host will score each email individually, and although we don’t know the exact criteria for each Host, we know the traits of spammy behaviour that Hosts penalise:

  • Not having an accurate Sender ID
  • Sending lots of emails that remain unopened
  • Sending emails that get marked as spam by the Receivers
  • Sending emails with a high volume of Hard Bounces and/or Soft Bounces
  • Sending emails with a high unsubscribe rate
  • Sending mass emails without an option to unsubscribe
  • Using all caps in subject lines, e.g. SPECIAL OFFER OUT NOW!!
  • Using some phrases that are common to spammers, e.g. pharmaceuticals/anything to do with sex/weight loss
  • Sending emails from a Sender Server ID or Server Domain without a Reputation
  • Sending emails from a Sender Server ID or Server Domain with a negative Reputation

There are more, but these are the main ones we can worry about. Every time the Sender sends an email, it affects the Reputation of their Sender Server ID and the Sender Domain. When we do things that spammy, our Reputation goes down.

We also need to build a positive Reputation in order for our emails to get through in the first place.


How to improve a Sender Server ID Reputation

If you’re sending mass emails from a standard Sender Server (not a Server designed for marketing emails) it won’t have an existing positive Sender Server ID Reputation, and you’ll be starting from a clean slate.

This where using a platform like MailChimp really helps, as they have multiple dedicated Servers sending millions of quality-checked marketing emails every hour. They will start you off with a positive Sender Server ID Reputation, and also force you to implement some legal/non-spammy formatting like unsubscribe links and defined Sender IDs.

It’s really difficult to grow a positive Sender Server ID Reputation using a standard email address, as the actual server is totally out of your control.


How to improve a Sender Domain Reputation

Improving your Sender Domain is much more within your control, but it’s also more time consuming! The only way to improve your Sender Domain Reputation is to not send Spam emails, and focus on sending emails that will be opened, read, and clicked.

Here are a few actions that will help this:

Introduce a Welcome Email or onboarding email series (I shared a banging Instagram post on this).

Welcome emails have a high open rate, so a nice way to demonstrate to Hosts that your emails are valuable

  • Cleanse your list regularly, MailChimp makes this super easy!
    • Remove all Hard Bounces
    • Remove any Receivers with 3 consecutive Soft Bounces
    • Remove Receivers who haven’t opened 5 emails in a row
    • Remove anyone with a one-star MailChimp rating
  • Give Receivers a reason to click within your emails. Use big buttons, add links to all your pictures and encourage users to visit your website.


Actions for the person who sent this question

  • Look at moving your mailing list over to MailChimp or an alternative marketing email platform
  • Add a welcome series for new sign ups
  • Start sending emails that gently encourage recipients to click through to your website
  • Subscribe to a couple of modern mailing lists and replicate their style. I absolutely love Glossier the makeup brand as they keep things ultra simple and achievable
  • Be patient. Your current Server Sender ID and Server Domain Reputations are currently too low to even reach spam folders, although we can address the Server Sender ID immediately, it’s going to take a little while to build up a positive Server Domain Reputation


Do you have a question about branding, websites or marketing?

I used to have an official ‘Ask Aime Anything’ feature on our website where visitors could send in questions, and where I could help I would post on the blog.

Oh how naive I was that I could keep that up. If you do have a question though, pop us an email – I’ll either point you in the right direction or add a new topic to my blogging to-do list.


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