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Spam email filtering: What it is and how to avoid it

Email filtering helps keep unwanted messages out of peoples’ inboxes—but you don’t want it to catch your client communication emails by mistake. Learn how email filters work and the best practices to avoid them. 

As an independent business owner, you work hard to craft engaging and valuable emails for your clients and audiences. When you’re email marketing, you’ll likely send helpful content and let people know when you have a special promotion or new service offering. You use email marketing best practices and labor over each message. 

 If you’re communicating with clients, you may send a questionnaire or an invoice. Of course, you want those emails to go straight to your prospects’ inboxes and not their spam folders. Here’s what you need to know about how email filtering works and how to keep your emails from being filtered into spam.

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What is spam email filtering?

Spam email filtering is a service that scans incoming and outgoing messages, flagging those likely to be unsolicited and unwanted—in other words, “spam.” Originally a brand-name meat substitute, “spam” now also stands for “sales promotional advertising mail” or “simultaneously posted advertising message.” 

According to Statista, spam accounts for over 45% of email traffic. Spam can range from a simple nuisance, such as unwanted sales emails, to dangerous scams with malicious links that can harm a user’s computer or steal their identity. For example, many spammers send phishing emails that mimic valid messages and solicit personal information.

A filtering solution shuttles those unwanted messages into a separate folder so users see less of what they don’t want and more of what they do.

How does email filtering work?

An email filter uses algorithms to identify potential spam. Those algorithms scan messages for standard features of unwanted bulk messaging. 

Common red flags for spam include:

  • Source reputation: A sender domain or IP address previously flagged for spam
  • High send rates: Too many emails from the same sender, indicating bulk sending patterns
  • Suspicious words: Heavy use of sales-y trigger words, such as “once in a lifetime opportunity” or “no catch”
  • Potentially malicious links: Links with generic or misleading anchor text, suspicious domains, or shortened URLs

Most contemporary email filters use machine learning, allowing them to better identify spam over time. If a user marks a specific sender as spam or repeatedly sends a certain kind of message to their spam folder, the filter will learn to flag those emails on its own.

Two kinds of spam email filters: inbound and outbound

Inbound email filtering is the best-known type of filtering solution. These kinds of email filters are likely pre-configured on your clients’ Gmail or Yahoo! accounts, and they prevent unwanted and potentially harmful emails from reaching the end user, usually by sending those emails to a dedicated folder the user can empty at will.

What’s an outbound filter?

Most email accounts today have inbound filters. Outbound filters are less common but can be essential for your digital reputation. Outbound email filters screen messages as they leave your network. Their primary purpose is to prevent spam messages and malicious links from compromising a sender’s IP address. For example, suppose that you accidentally download malware onto your computer. You then send a client invoice that is also infected. The recipient’s inbound filter could pick up on that malware, and you could end up on an IP blacklist. Addresses on blacklists are much more likely to get caught in spam filters.

Outbound filters also pick up messages sent from a network without the network owner’s knowledge. This may happen if an employee uses their professional login credential to send personal spam or if a scammer steals someone’s credentials. Either way, the filter keeps the company’s IP address from being associated with spam and criminal activity.

How to avoid getting emails stuck in a spam filter

When you run a small business, every message matters. Prevent emails from going to spam—yours and your clients’—by following these email best practices.

Use a custom sender domain

Your email sender domain comes after the @ in your web address. Send all business emails from your domain instead of a personal account such as your Gmail or Yahoo, if possible. Large-batch emails from one of these servers are much more likely to go to spam. Fortunately, getting an email domain from your web hosting provider using the same name is easy. This lends credibility to your emails and helps you to build a reputation as someone who sends great, useful emails—not spam. If you don’t have a website yet, don’t worry. You can get a custom domain from various sources, including Gmail. And, if you have a custom domain through Gmail and you’re a HoneyBook user, you’ll be able to check your domain authentication protocols directly from your HoneyBook account. Authenticating your email address is key to ensuring email deliverability.

Use a double opt-in

By definition, spam is unwanted and unsolicited email. Make sure you’re only sending messages people actively want to receive.

First and foremost, only send messages to people who have signed up to receive them. An opt-in form on your website makes it easy to obtain these addresses. Once you have the form set up, you’ll identify dozens of opportunities to link to it and collect legitimate email addresses.

People may forget they’ve signed up, so add an extra layer of protection by requiring email confirmation. This is called a double opt-in. When people sign up for your list, you send a confirmation email asking them to confirm the address. This clarifies that you have their interest and reduces the likelihood they’ll report you as spam.

Prioritize authenticity (avoid trigger words)

A common piece of advice for avoiding spam email filters is to review online lists of spam trigger words to ensure your emails don’t sound spammy. There are dozens of similar lists, many with hundreds of words or more. This is good advice, but we want to lead with a different angle: make sure all of your emails sound authentic and human. Think about trigger words, but primarily focus on offering instead,  real value specific to your clients’ interests and your business’s offered value.

Choose your links carefully

Misleading links are another major red flag for spam filters. Every time you include a link in an email, check that it meets all of the following criteria:

  • The anchor text—the text that people click to follow the link—is specific and relevant to the destination page. 
  • The URL is readable, and you haven’t used a URL shortener tool.
  • The target page has valuable information that relates to your email content.

Most importantly, avoid using more links than you need. Extra links raise red flags for spam and distract readers from the necessary links on your site (like the one to your landing page).

Check your spam scores

If you’ve followed the listed recommendations, you have a good chance of escaping spam filters. It holds true that those filters can be quite demanding, and they’re not always perfect at reading your intentions.

A spam email tester will give you peace of mind. Simply send a copy of your email to a free online tester, such as Mail-Tester, and get a detailed report showing what you can improve. This step is beneficial when you’re new at sending bulk emails.

Improve client relationships by avoiding the spam folder

Top-notch client communication is an essential ingredient for business growth. Staying out of spam folders is the first step because it ensures people see what you have to say.

One-on-one messages are equally important, though, if not more so. HoneyBook can help you engage with your clients in a number of ways. HoneyBook helps you connect with each client by giving you a central place to view their information.

Manage client relationships from one place

Connect your lead management with your client qualification questionnaire and never miss a chance to connect.

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