Content Filtering and Email Deliverability – Everything You Should Know

Content filtering is a powerful cybersecurity tool. It protects people and businesses from exposure to inappropriate and harmful web content. But, what if you are on the other side of the fence? All your marketing efforts will amount to nothing if your content gets filtered out. And without sufficient exposure, your campaigns are sure to fall flat.

What is content filtering and who uses it?

Content filters are designed to screen and restrict access to harmful and objectionable content. The filtering process mainly focuses on webpages, emails and exe files. In other words, any content that can harm the end user when accessed accidentally or on purpose.

As a security strategy, content filtering is used by businesses, libraries, schools and households. Businesses use content filtering to control employee web behavior and restrict access to objectionable content. This protects companies from a multitude of problems.

content filtering algorithms decide if your emails get through

First, it increases the level of data security. Content filters restrict access to sites hosting malware and other harmful content. Content filtering also blocks access to adult sites and prevents download of copyrighted content. Companies can be held liable if such data is found on their internal networks and servers. It also prevents people from engaging in non-work related activities at the workplace.

How content filtering affects email deliverability

ISPs consider several key aspects when it comes to differentiating spam from desirable content. Email origin, sender reputation, content quality and subscriber engagement. Content filtering is an integral part of the spam filtering process. Other components include source and reputation screening.

ISPs block emails or sender IPs as a way to protect their users from unsolicited content. The process is not infallible and sometimes legitimate senders get filtered out.

Since the success of your campaign relies on good deliverability, you need to know how your content can affect it. Click To Tweet

Content filters screen incoming email for spam triggering words, phrases or characters. The screening involves every part and aspect of the email. Subject line, header, footer, images, color, font, links, attachments, etc.

If an email component matches the spam filtering rules, the email goes to trash or gets blocked. This, in turn, affects your reputation and deliverability.

Subscribers also play a role in the way your ISP handles messages. If your emails get labeled as spam or deleted, it sends a signal to the ISP that your content is undesirable.

User engagement is a key criterion when it comes to content filtering. So, do your best to keep your audience happy and engaged.

Best strategies for great content and high deliverability

Experiencing delivery issues is inevitable in the email marketing business. You may be doing your best to adhere to laws, good sending practices and user satisfaction. But a percentage of your legitimate permission-based emails will still end up in the junk folders. People forget they signed up or their interests change. As a result, they hit the spam button.

Besides, there is no way to avoid the spam filters. All incoming emails go through the screening process. The thing is to get a passing grade and make it to the inbox.

Let’s continue and look at some ways to increase your odds of passing the ‘spam exam’ with flying colors.

Avoid URL shorteners

Using short and nice looking links in your emails instead of ugly, long ones is tempting. Unfortunately, URL shorteners are often used by spammers, which makes them a deliverability risk.

Spammers use popular URL shorteners such as to mask harmful links. And these links often redirect to sites that may install malware or steal personal info. As a result, URL shorteners are included in most major blacklists.

If your emails contain a link to a blacklisted domain, they may not reach your users at all. So, it’s best to use full URLs whenever you can to ensure inbox delivery.

There are other alternatives you can consider. You can create your own custom link shortener by purchasing a shortened domain of your own.

You can also link long URLs to text or images in your HTML version emails. This will hide the URL without jeopardizing your deliverability.

Choose your images wisely

Images are a great way to create attractive email marketing campaigns. But don’t overdo it or your own efforts will get your emails into the junk folder.

Spammers often send emails that are one huge image. Or they use too many images and little text. It’s a known tactic to bypass the spam filters since they are primarily keyword-based.

To prevent spam from sneaking into the inbox, most ISPs will filter these messages out. You can avoid getting caught by this filter by keeping a good text-to-image ratio. Aim for 80/20 in favor of the text.

Bonus Tip: If you're using images in your email marketing - always use alt text so people know what the image is about even if it fails to display in the message.Click To Tweet

Keep in mind that image-packed emails tend to load slowly. They also may not display properly on all mobile devices. Some email clients don’t automatically display images. These email clients actually have a default setting where they do not download the images and just show a blank space. Of course, people can change the client settings to enable automatic downloading of images.

Most people, however, do not bother and just abandon the idea of viewing your email. Only the most enthusiastic subscribers will do this. It’s more likely they’ll click the spam button or delete your emails. So, make sure that you have enough content to convey your message even if images are not being displayed.

Don’t neglect your subject line

Most of us decide whether to open or delete an email based on what we see in the subject line. With the sea of emails we receive every day, we tend to open those that catch our eye and delete the rest to avoid clutter.

So what can you do to make sure your subject line does the job? First, keep it brief but clear, not more than 50 characters. Use the right words and phrases to entice your subscribers to open and read the email.

Avoid spam triggering words. Although they are attractive and persuasive, the content filters associate these phrases with spam emails.

Here are some words and elements that can trigger the spam content filters:

  • free
  • winner
  • guarantee
  • bargain

The same goes for using all caps, exclamation points, dollar signs, and special characters.

There are many tested words and phrases you can use as an email marketer. But the only way to know what works best is to test. Experiment with different subject lines and trigger words. Good email marketing platforms have a split testing tool you can use for this purpose.

Proofread your content

One of the easiest ways to ruin your email marketing efforts is to send emails with spelling errors. Never send out your campaigns without a spell check.

Poor grammar, typos and punctuation will trigger spam filters since these elements are hallmarks of spammers.

More importantly, it will jeopardize your business credibility and devastate your sales figures. Emails full of spelling errors are an effective sales deterrent. With all the internet frauds going around, people are naturally cautious.

So, they are unlikely to buy from you if you appear suspicious in any way. The end result is – they will probably label you as spam or delete the email.

Poor grammar and typos are the fastest way to get mistaken for a spammer. #email-marketingClick To Tweet

proofreading is important for content filteringTo be absolutely certain that your emails are error-free, don’t leave anything to chance. Run all of your content through the spell checker. This is the least you can do as an email marketer.

But this is not enough. The spell checker doesn’t always catch commonly confused words or phrases. For example, which – witch, heard – herd or sore – soar. And you certainly don’t want to make your business sore. These emails may generate giggles, but they won’t generate many sales.

It’s a good idea to print a copy and have someone else give it a once-over just to make sure you haven’t missed anything. One of the easiest ways to ruin your email marketing efforts is to send emails with spelling errors.

Avoid HTML-only messages

A common error with email campaigns is sending HTML-only versions without a plain text alternative. Here’s why you should abandon this practice.

Not all people use email apps that support an HTML view. Also, some people choose to disable the HTML view. As a result, HTML-only messages may not get displayed as a readable copy to all recipients. All they’ll see is an undecipherable computer code.

avoid html only emails

Keep in mind that HTML-only messages tend to get filtered out by the spam filters. On the other hand, you don’t want to miss out on the benefits of HTML: nice designs, images, styles and text colors.

To avoid this, consider sending your emails as both plain text and HTML. This way, if their email client supports the HTML view, it will appear by default. If not, people will see the text version.

Be sure to check your HTML before sending emails off. A broken HTML code will prevent the message from displaying properly. As a result, you’ll risk deletions and spam complaints.

Avoid link overload

As with images, don’t do what spammers do. That is, send messages with little text and too many links that have nothing in common. First, the content filtering will misidentify you as a spammer. Secondly, emails with a handful of sentences can hardly be called valuable content. Failure to provide value will cause your subscribers to disengage.

Make sure all your links are relevant to the content and consistent with your message. Instead of just saying click here, explain what clicking on the link will do.

All links should take the subscriber to the promised destination. Check them and see if they work before launching your campaign. Never mislead your subscribers by promising one thing and taking them someplace else.

Be sure to consider the following as well:

  • Place your most important links at the beginning of the email to get more click-throughs.
  • Do not forget to insert social sharing and forward buttons to help spread your message and brand.
  • Include “unsubscribe” and “edit subscription” links so people can opt out or change preferences.
  • For user convenience, be consistent. Always have the above links in the same location in all emails.

Observe anti-spam laws

Before you start working on your campaigns, inform yourself about laws governing email marketing. Email marketers in the U.S. must abide by the CAN-SPAM Act. Otherwise, you face fines for non-compliance.

The Act regulates sending of commercial emails as a way to combat spam and protect user privacy.

As a legitimate marketer, you’re probably already following good emailing practices. But there are certain elements you may overlook and accidentally violate the Act.

Overall, here’s what you need to know:

  • Always use permission-based address collection methods.
  • Never use deceptive header information (“from” field, subject line and “reply-to” address).
  • Include a valid business postal address in your emails, such as a street or postal box address.
  • Disclose clearly that your message is an advertisement.
  • Include a clear and understandable opt-out option. To stay compliant, place an unsubscribe link in a prominent location.
  • You must process all opt-out requests at once and remove these addresses from your list.


inform yourself about laws governing email

Personalize your content

Your present content affects your future campaigns. You have to create awesome campaigns today to ensure high user engagement and deliverability rates. Keep your content clear and user-friendly.

The purpose of email marketing is to connect with your subscribers. To ensure relevancy, you should create your campaigns with your audience in mind.

Above all, each of your campaigns has to deliver value and live up to the promises you make upon signup. Avoid technical terms and convey your message in a language your audience can understand.

Also, don’t send the same email to your entire subscriber base. Segment your mailing lists and personalize the content to match people’s interests.

For optimal user experience, you can use the following categories to segment your lists:

  • demographics (age, gender, location, income)
  • job title, business size, past purchases, payment plan or status (customer or prospect)
  • sending frequency (weekly, monthly newsletters)
  • type of content (special offers, promotions, educational content)

Choose a reputable email marketing platform that cares about your success

You’re probably a busy person and cannot afford to waste time where it isn’t absolutely necessary. Your email marketing campaigns shouldn’t take weeks to set up and deploy.

With Emercury at your beck and call, you don’t have to worry about any of this. Whether you are a marketing guru or a novice, we’ll help you design the best campaigns.

Emercury is ready to support all of your campaign efforts. Content personalization, split testing, email automation, tracking user responses and much more. Our specialists will be happy to assist you with list optimization, deliverability and content design.

Getting started with Emercury is so easy. So go ahead and give it a try today.

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