Any good marketer should aim to grow a high-quality email list, develop amazing emails, and produce awesome content. But, even if you have all of these aspects in the bag, this doesn’t mean you can skip and avoid spam filters.
There are many things that affect one’s email deliverability and these factors are what ultimately determine whether your messages will reach their intended destinations or not.
As an email marketer, you should make it a habit to stay vigilant whenever you send messages to users in your contacts list. Learning how to avoid spam filters is a critical skill that you should have in your toolbox to get the most clicks, opens, and conversions from your email marketing campaigns.
In this post, we’ll discuss how spam filters work, the good and bad signals to look out for, and tips on how you can prevent being added to one of these dreaded filters.
Before we talk about how to get past spam filters, let’s first analyze what is a spam filter.
What Is a Spam Filter?
A spam filter is a software protocol that is used to identify unwanted emails and prevent them from reaching a user’s inbox. Internet service providers (ISPs) are the primary users of spam filters since they want to make sure that their servers aren’t sending out spam to their users. However, small-to-medium-sized businesses (SMBs) also leverage spam filters to help protect their workforce and assets.
Both inbound and outbound emails are subjected to spam filters. ISPs must utilize these two methods especially since spam messages account for approximately 14.5 billion messages per day. For SMBs, they typically concern themselves with just the inbound messages they receive.
There are numerous spam filtering solutions available today. You can find them hosted on computer servers, integrated into email software, and hosted on the cloud.
How Does a Spam Filter Work?
Spam filters work by using methods known as “heuristics” which means each email must be put through numerous predefined rules or algorithms. Each rule places a numerical score to assess if the message that was received is spam.
If the assigned score passes a certain level, the email will be labeled as spam and prevented from proceeding any further.
There are various types of spam filters and they each have a different approach to identifying spam.
Content Filters
The job of content filters is to examine the contents of an email and use that data to decide whether or not it should be marked as spam. Spam emails are usually easy to predict even by machines, especially since they tend to have similar objectives.
A spam email often promotes explicit material, offers unique deals, or otherwise takes advantage of human desires, feelings, and emotions like fear or greed. Content filters typically look for words associated with money such as “limited time” or “discount” so this is something email marketers should be aware of. Triggering this type of filter simply requires you to use these target words a certain number of times.
Content filters could also assess a message for inappropriate language that might indicate explicit content inside. Some tricky attackers use sexually explicit emails to bait users into opening their emails and clicking on links that cause their systems to be compromised.
Blacklist Filters
A blacklist type of spam filter stops messages from senders who have been added to a list of spammers. These blacklist filters are constantly being updated since spammers can easily change the email addresses they use.
A spammer can switch back and forth between email domains so that their emails can still penetrate the filters. They can only be prevented once the blacklist filter has been updated and the sender’s message gets marked as spam.
Organizations may also use their own blacklist spam filters to provide added protection to their assets. For instance, they can use the filters to prevent headhunters from recruiting their employees to other companies. Another way they can use a blacklist filter is to prevent emails, such as discounts and other sales offers, which could distract their staff from completing their tasks.
Some of the most recognized blacklists are: ZEN from Spamhaus, SpamCop Blacklist and CBL Blacklist
Rule-Based Filters
A rule-based spam filter is used by organizations as it allows them to set specific rules that can be applied to all messages that arrive in their network. If the content of an email or its origin is flagged by one of the rules, this can be sent to the spam folder automatically.
For instance, users can set this filter to search for specific keywords or phrases within the body of an email. If any of these terms are present, the email gets redirected to spam. It’s also possible to set the filter to find particular words or phrases in the email header section.
Besides targeting headers, rule-based spam filters are also useful for assessing certain senders. You can set this type of filter to look for details in the domain the message was sent from or even the name of the user behind it.
Bayesian Filter
A Bayesian spam filter is used to learn the preferences of a user by analyzing the messages that they send to the spam folder. It takes into account the content of these specifically marked emails and then sets up its own rules accordingly. It then applies all these rules to all future emails that try to reach your inbox.
For instance, if you regularly mark all emails from a certain individual as spam, a Bayesian spam filter will recognize this pattern. It will then be on the lookout for any more emails that come from this particular sender and will automatically direct them to the spam folder.
Header Filters
The header type of spam filter analyzes the header of an email to check if it was sent from a trusted source. This may involve checking the IP addresses that spammers frequently use.
The filter could also find data indicating that the message is just a single copy of many that were sent to pre-organized mailing groups.
Language Filters
Spammers can sometimes target users from different countries and the message sent to them is in a foreign language. In most instances, people only want to get emails in languages that they understand.
It’s important to note that there is no one approach that provides a complete solution to getting rid of spam. There will always be a trade-off with a specific type of spam filter. The processes behind these methods are constantly trying to find a balance of whether it should accept or reject an incoming email.
Good Signals for Spam Filters
The following are the ideal signals you want to have so you can avoid being flagged by spam filters:
● Open: Users that frequently open your messages are considered a good signal that your email marketing campaign isn’t producing spam content. This also helps improve the chances that your emails will reach their intended destinations.
● Reply: People in your mailing list that respond to your emails are viewed as a good signal and it also helps improve your reputation among email providers.
● Move to folder: Recipients who move your messages to different folders within their inbox are a sign for email providers that users care about your emails. Providers will consider your emails to be important and will more likely allow them to be delivered to their respective inboxes.
● Add to address book: Recipients who include your email address in their address book are seen by email providers as a positive sign that they are interested in receiving messages from you.
● Not junk: Users who move out your messages from the junk folder are seen as a significant and positive signal by email providers. They will be more inclined to label your email campaigns to be worthy and relevant of making the inbox of their members.
Bad Signals for Spam Filters
These are the signals that spam filters assess carefully before flagging for spam:
● Move to junk: Recipients who move your messages to the Junk folder are an incredibly negative signal that spam filters take seriously. Email providers will see your campaigns as unworthy of reaching their intended destinations.
● Delete without open: Users who just check the sender and subject of messages and then immediately delete them are also a strong yet negative signal that email providers look into.
When all the good and bad signals are combined, they result in two unique scores, namely:
● The score you have for the individual subscriber: Individual users who are always opening your email campaigns and transferring them to folders will let you build up a score with them.
● The score you have with an email provider: If most of your subscribers from a specific email provider are opening and moving your emails to folders, then you have a good chance of building up a good reputation with this provider.
Email providers, such as Gmail, take these two reputation scores into account when deciding whether they should let your latest email campaign reach its destination or not.
For example, you may have a good reputation with an individual subscriber who constantly opens your messages. However, if your reputation score with an email provider is negative for whatever reason, then no one will get your emails even if you are sending them to engaged users.
Tips on How To Avoid Spam Filters
Now that you’ve learned more about spam filters, it’s time to discuss the general tips to follow on how to avoid spam filters.
1. Choose Your Opt-In Method Wisely
One of the most important things to avoid being flagged by spam filters is to make sure that your email subscribers do want to hear from you. That’s why there are various opt-in methods nowadays that can help you with this regard.
Upon subscribing, you want to send another email out to your subscriber asking them to confirm if they want to receive messages from you in the future. This double opt-in approach helps ensure that your mailing list stays clean, including your domain reputation.
There are also other signup methods that allow for single opt-in and they can be effective as well. Ultimately, you want your recipients to give you permission that you can email them.
2. Limit the Number of Links In Your Email
Today’s spam filters are hard on emails that contain numerous links. This is probably because spammers tend to use links throughout their messages in the hopes that the reader will at least click on one of them.
What you can do instead is to have just one or two links in your email but ensuring that you have them placed prominently. Although this doesn’t guarantee that your message won’t be flagged, it can still improve your chances of getting past spam filters.
3. Don’t Use Words That Could Be Perceived as Spam
Since spam filters analyze the content ofemails, it’s essential for email marketers to be careful with what they include in their messages. Although there are no magic keywords that can improve deliverability, limiting the use of words that have a higher chance of being flagged for spam can help.
Words such as promo, buy, free, discount, earn, winner, and order are some of the terms you should use sparingly.
4. Avoid Using Purchased or Rented Contact Lists
Buying or renting email lists is definitely not something you want to do as an email marketer. Not only is it in direct violation of the terms of service for your ISP, but it is also going against the CAN-SPAM Act.
Transferring or selling email addresses to other email lists is illegal and frowned upon. It also violates the privacy of users whose addresses are on these lists, especially since they haven’t given you permission to contact them.
5. Segment Your Lists to Avoid Sending Irrelevant Campaigns
Instead of sending the same message to your whole email list, you should try segmenting instead. Targeting email campaigns to users who you know will be interested in your message is more effective.
This will help increase the number of recipients who open your campaigns and also reduce the number of those who delete them. It’s important to send positive signals to email providers to showcase the validity of your email marketing campaigns.
6. Grow Your Own Email List
The content of your email is essential to communicate the value your business has to customers. However, it won’t benefit your recipients if your message doesn’t arrive in their inboxes.
That’s why you want to have an email list that consists of users who are interested in receiving emails from you. In this way, you ensure that they will engage with your messages.
Choosing to build your email list organically is one of the best decisions email marketers can make today. Although it may not be the easiest and fastest way to grow your list, it is by far the most effective.
7. Leverage Email Authentication Protocols
Email authentication may sound technical, but it is key to verifying to providers that you are a legitimate email sender and that your emails are valuable to their recipients. Inbox providers rely on email authentication and will not look favorably on those that aren’t authenticated.
The following email authentication methods should help prove to providers that your messages are worthy of reaching their inboxes:
● Sender Policy Framework (SPF): An SPF confirms your identity as an email sender by providing a comparison of your IP address with a list of others that are authorized to send from your domain.
● Domain Keys Identified Mail (DKIM): A DKIM ensures that your message hasn’t been tampered with while on route to its destination.
● Domain-Based Message Authentication Reporting and Conformance (DMARC): A DMARC makes use of both SPF and DKIM by requiring these two to send and deliver emails.
● Brand Indicator for Message Identification (BIMI): A BIMI attaches the logo of your business to emails so that your recipients can easily recognize you as the sender.
Leveraging these authentication methods is your responsibility as an email sender. It’s crucial that you authenticate your emails before sending them to ensure the highest probability of gettingpast spam filters.
8. Clean Your Email Lists Regularly
The subscribers in your email list may no longer be using their accounts or have moved on to different interests. It’s normal if some individuals simply don’t want to receive your messages anymore.
The important thing is that your email list has a quality list of contacts that you can send at any time.
Although some users may unsubscribe, others may mark your emails as spam or simply just ignore them. This is not a good sign for your sender reputation as it can make your messages less likely to reach their intended destinations, even to those who are actively engaging with your campaigns.
That’s why having a leaner yet more engaged email list is more beneficial than a large one with unengaged users.
Regularly maintaining your list can help you avoid low engagement as well as its effect on your sender reputation. Taking out bounced emails, uninterested users, and other potential spam traps can be incredibly effective in cleaning your list.
Keep in mind that it’s normal for people to unsubscribe to your list so don’t take this personally. The important thing is to stay proactive by ensuring your email list is clean and has high-quality contacts.
9. Stay Away From Deny Lists
A specific sending reputation is associated with each email domain. Once this starts to fall off, you may find your account on one of the many email deny lists today.
Even the most meticulous and legitimate senders can still end up in these email deny lists. You can reduce the chances of finding yourself in these lists by:
● Using double opt-in or confirmed opt-in to ensure your recipients are engaged
● Set up a sunset policy to take out subscribers who are no longer interested in your campaign
● Leverage real-time address validation to minimize the risk of typos or false emails ending up in your list
Checking your delivery rates can help provide you with information on whether or not you’ve been added to an email deny list.
10. Keep Track of Your Email Engagement Metrics
Monitoring your email metrics and performance are two ways you can ensure your email marketing campaign continues to progress and improve. But, before you can use these key performance indicators, you should first understand what the baseline metrics mean.
You want to start with the following:
● Open rates
● Click-through rates
● Delivery rates
● Spam complaints
When tracking these metrics, you shouldn’t worry if you start noticing negative trends pop up. Instead, you should stay calm but act quickly so you can remedy the issue immediately. For instance, if you notice your open rates are starting to drop, review your email frequency and subject lines to see if changes here can affect this metric.
If testing emails, you want to use real content as well as recipients. Some techniques such as seed testing can let senders test their emails by sending messages to a small batch of recipients to see how an ISP responds. However, seed testing doesn’t provide users with an in-depth analysis.
Instead, you should do your tests on real users to get more accurate information on how they respond.
11. Ensure Your Content Is Relevant
The primary success factor of any email marketing campaign is the commitment of its sender to provide interesting and relevant content to its recipients. This means that you should be intentional when you send messages and not just click the send button for the sake of it.
Aimless sending can result in lower engagement rates, which is what you should avoid as an email marketer. You want to ensure that your messages resonate with your recipients.
Ask yourself the following questions when drafting your next email:
● Is the content I’m about to share relevant, urgent, or new information to my recipients?
● Have I already shared an update on this topic lately and is it too soon to send another one?
● Do all of my email subscribers need to know this information or should I just send this to a specific segment instead?
● Will I find the content of this message valuable as an email recipient?
Finding the right mix of email content that works best for your business usually involves trials and tests. Feel free to experiment and try new styles of your copy to see which is most effective.
12. Stay Compliant
Although being compliant doesn’t guarantee 100% email delivery, it can still help you get past some roadblocks in sending emails.
As an email marketer, you should already be familiar with the CAN-SPAM Act, the General Data Protection Regulation (GDPR), the Canada Anti-Spam Law (CASL), and the California Consumer Protection Act (CCPA). All of these laws govern how commercial email should be sent and are vital for email deliverability.
● CAN-SPAM Act: This act protects recipient privacy by requiring email senders to follow a set of sending standards and rules that aim to weed out malicious actors. Under the CAN-SPAM Act, email senders should avoid any form of deception in their commercial email communications. Senders should always be transparent with recipients throughout the sending process.
● GDPR: One of the most talked-about pieces of legislation recently, GDPR covers data privacy for users within the European Union. This means that anyone who sends an email to this region should be compliant to avoid being flagged.
● CASL: The CASL law has the same function as the CAN-SPAM Act as it aims to provide more transparency between email senders and recipients. However, CASL applies specifically to commercial electronic messages or any electronic message that promotes taking part in commercial activity.
● CCPA: Although the CCPA may appear similar to the GDPR, the act only applies to businesses that fall within certain categories. There are specific requirements that email senders should know about the CCPA and it’s important to know about them to stay compliant.
As an email sender, you should be compliant with these pieces of legislation. Meeting the requirements of just one of these laws or acts doesn’t mean that you won’t get flagged for the others. It’s important to stay as compliant as possible to maximize your email deliverability.
Stay Vigilant to Avoid the Filters
Following the best practices in email deliverability can give businesses an advantage over their competitors. So, as you go about working on your campaigns, you should consider the tips that have been provided in this guide. All of the information provided in this post is intended to educate email marketers like you on how to avoid spam filters.
By following the best practices in sending emails, you not only improve your open and click-through rates but also give out positive signals to email providers. These signals should help ensure that your future emails can reach their intended inboxes.
Filter out the Obstacles on Your Way to a Better Inbox Placement
Learning how to get past spam filters may not be the priority for most email marketers, yet doing so can have a huge impact on the results of most email marketing campaigns.
Our mission is to help you reach the best results out of your marketing efforts. We help you achieve your marketing goals with our many services we provide. From seed testing and spam filters to email authentications and gmail tab monitoring we make sure your email campaigns land in the right place.
