Email Algorithms: What it Takes to Get into Inboxes

Posted by Sarah Wai on Feb 24, 2020 4:34:52 PM

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When we talk about algorithms, it's usually in the context of the factors you need to consider for ranking in the search engines. But did you know that email also has algorithms that determine whether or not you get into someone's email inbox? Say you write an email to send to many of your leads. You've drafted (what you think) is an incredibly persuasive email--perhaps one of the best you've ever written. You send it out, excitedly anticipating a great response to it. A few days go by, and you haven't gotten a single response.

What happened? Did anyone get it? Did they read it if they did get it? Are they upset that I sent that email?

It can be hard not to take the lack of response personally.

If you have HubSpot software, you're able to see this kind of info after an email has been sent out. You'll see exactly who opened, who clicked through, who didn't receive it and why, as well as additional helpful information. If you don't have access to that kind of info (because you don't utilize software that provides it), you're just left guessing at what happened, and that can be unnerving.

Whether or not you have access to these kinds of analytics, there are a few things that are important to know when it comes to sending emails and how to conquer email algorithms.

Email Terminology to Know

When email first became "a thing," it was a simple process of sending and receiving messages. Then features like the Junk folder happened, and SPAM laws were passed, meaning that email got a bit more complicated. Email has evolved immensely over the decades, and it can be hard to grasp just how much or understand what has changed. First, here is a little email vocabulary lesson that will help you understand the key factors in email algorithms. 

  • Email Client: The most popular email clients include Google, Outlook, Apple Mail, and Hotmail. These web applications are designed to write, send and receive email messages, and they all offer different features and can have different email algorithms.
  • Sending Domain: A sending domain is the web address that indicates who an email is being sent from. This allows recipient mail servers to authenticate your messages and identify spam. For example all emails sent from Tribute Media use the sending domain of "" If you have a free email that you set up with Google, it's sending domain is ""
  • Email Deliverability: A term used to describe the process of allowing emails to reach recipient inboxes. Things that affect deliverability include Internet Service Providers, bounces, spam issues, bulking, etc. Learn more about email deliverability. 
  • Email Sending Authority: The gauge for your ability to get into recipients inboxes is based on both the credibility of your sending domain and the reputation of the email marketing software you use. (See info on Paid Email Services below and how those affect this.)
  • Blacklists: Everyone knows what a blacklist is, but when it comes to email it essentially means that there is a database that contains known sources of spam and it's used to filter out and block questionable emails that have similar qualities. Unfortunately, the majority of email sent worldwide is spam. And whether or not you know it, you've more than likely been labeled as spam at least once. If you've been labeled as spam many times, you're likely on a blacklist, and that's a terrible place to be. This is why buying email lists or emailing people who aren't expecting to hear from you (or hear from you too late) can be so detrimental.
  • Spam: Typically described as an unsolicited email that is often sent in bulk and is fraudulent or has malicious intent. They typically include links that lead to sites hosting malware or phishing sites. They can be used to capture private data, pretend they are a recognizable sender to mislead recipients to provide private information or click on a toxic link, or harvest files from computers or networks, or infect computers and networks with viruses. Learn more about the CAN-SPAM act. 

Free Email Services vs. Paid Email Services

Most people don't understand how this difference can affect your ability to get into inboxes, so here it is.

Free email services through Microsoft and Google are great for personal email sending and receiving. If you are a business that is constantly using a free email account for business purposes, I recommend not doing so anymore. Although it can work for a while, eventually, you are likely to see a drop in responses and clients saying things like, "I haven't been getting emails about your upcoming sales and I know I signed up to be." The reason for this is typically because spam filters are routing you to Junk or Spam folders, or refusing to let you into inboxes altogether (yes, they can do that).

The best way to combat that issue is to set up a paid email service. Yes, you have to pay for it, so that seems like a less-than-ideal option. But ask yourself this: would you rather pay a little to ensure you're generating more business, or opt for a free service and lose out on business? That is really what it can come down to. The main reason being that most email providers see professional email addresses such as as being far more credible than if you were to have a generic free email address that ends with Your odds of getting into inboxes greatly increase if you have a paid email service, so trust me when I say it's worth the investment.

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Email Marketing Software

First, if you are trying to send bulk email directly through your email client (usually done by having one visible recipient and MANY additional recipients as blind carbon copies-BCCs), you are either going to a spam folder already or well on your way. You need email marketing software in order to compose one email that can be sent directly to numerous recipients at once.

It is also important to note that not all email marketing software is created equal. As mentioned above, the reputation of the software you use to send bulk email is a factor in deliverability. At Tribute Media, we trust HubSpot because they are known for fiercely protecting their sending authority. This is done by, essentially, policing how people are using their software. Yes, it does mean that, as users, we are subjected to an occasional verification process, but it's well worth it to maintain the integrity of our email sends. 

So how do you know if you are using a software with a good sending authority? It's not really something they have to disclose or share publicly, but it's usually a safe bet that the people who are abusing email marketing are doing so in the free tools. It pays to pay a few bucks to ensure you are using a reputable software that's reputation is built on honest people doing honest email marketing on the up-and-up. 

Make Love, Not Spam

I have a t-shirt from a marketing conference that has the phrase, "Make Love, Not Spam" on it and it's one of my favorites. Obviously, you're probably not one of those people sending mass amounts of emails in an attempt to spam people. However, you may be creating emails that are flagged for doing so. (Here are some do's and don'ts of effective email marketing.)

Billions of emails are sent worldwide every day, and they are one of the most cost-effective ways to reach people. Because they are so cost-effective and prevalent, they are a great tool for abuse and spam, which is why email algorithms and email filters have become so crucial. It's important to ensure that you are doing everything in your power to avoid seeming like spam so that you can beat the email algorithms and land yourself in the right inboxes. Check out our Step-by-Step Guide to Email Marketing for more information on creating great emails that make it into inboxes and convert!

Sarah Wai

Written by Sarah Wai

Former Content, Email, and Social Media Marketing Specialist of Tribute Media. Bachelor of Science in Digital Communication Arts and Master in Business Administration.