Top tips to avoid email spam filters

Thankfully, the volume of spam emails is falling. As a percentage of total emails sent, spam now accounts for just 48% compared with a mighty 71% in 2014. Whoa!

Let’s revisit two words from this paragraph:

• Thankfully – as an email sender, you’re an email reader too. How frustrating is it when your inbox is full of unwanted email? You know you should spend some time on Unsubscribe, or your Outlook rules, but how can you fit that in alongside your day job? Don’t you wish the spam filters were more effective, better at spotting the spam that comes your way?
• Just 48% – even today, almost half of all emails sent are spam! Perhaps the spam filters are actually doing a good job.

How about sending emails – circulating an automated email to a list.

• What is it about your email that makes it not spam?
• Are you offering the reader a genuine opportunity or valuable information?
• Are you adding value based on their specific interests, is your automated email based on a recent interaction on your website or follow up on a purchase they made recently which has specific relevance to them.

Whatever the reason, you need to get past the spam filters and persuade the recipient to read your email.

Here we take a look at how the ISP spam filters work and therefore how to best avoid them.

Why are there spam filters?

Spam filtering is carried out at many levels. Email Service Providers (ESPs), Internet Service Providers (ISPs), company IT departments and individuals can all set their own filtering. It’s a means of eliminating timewasting content and malware. It’s also the law – countries such as the USA, Australia and the UK all have legislation to protect businesses and individuals from spam.

How do ISPs and ESPs detect spam sources?

Spam traps

These are false email addresses deliberately set up to catch spam emails. They are typically included in a hidden form, for example on a webpage. A scammer may harvest the content of the web page in order to build an email circulation list. If an email is sent to the false address it is detected en route and known to be spam.

Inactive email addresses

An email sent to an inactive address is normally “bounced” by the ESP. If further emails are sent to the same address, this will trigger a spam alert. Sending an email to a circulation with a high proportion of inactive or bad addresses will have the same effect.

Blacklisted domain name

Email originating from one of a list of known spam senders, or senders who are not expected to send emails – such as proxy servers

What are the consequences?

If an email is evaluated to be from a spam source, it will be blocked and the domain name of the sender will be added to a DNS blacklist. This will prevent any further emails being sent and will take a long time for the sender to rectify.

How to avoid spam filters

Use a credible sender name

Use a From field of firstnamelastname@domain. ESP filtering places emphasis on the From field, as the ESP can use it to gauge the validity of the sender. This will also increase the chance that the recipient will open the email. The alternative, such as noreply@ or 123abc@ will flag up to the ESP and may also put off the recipient.

Blacklist check

If your company has had blacklisting issues, check that the domain name is clean. Sites such as MxToolbox can check a mail server address against known DNS blacklists. Specialists such as Return Path can improve the chances of success by establishing the sender as bona fide.

Spam test

Before sending your email, check it using a tool such as Mail Tester which tests it for spammyness

Don’t re-use other people’s email lists

Particularly don’t buy an email list, it may contain spam traps or many inactive email addresses.

Check for bounced emails or inactive recipients

Most bounced email addresses are reported by the ESP immediately, although sometimes there may be a repeated attempt to send. Keep track of these and update the address list. Also, check for inactive recipients – they may have subscribed previously but no longer open the emails.

Ask subscribers to add you to their contact list

This will mean you are whitelisted.

Action unsubscribes

If a recipient has taken the time to unsubscribe, make sure it happens. It’s the law.

Avoid known spam keywords

Spam filters will latch onto subject lines containing words such as Viagra, free, cash, deal, debt. Within the email body, the filters may allow the word to be used, depending on the context.

Keep the email textual

Images and smart features can make the email more enticing, but they may break the spam filter’s rules. When including images, keep the image small, as large images may be rejected. Be careful when adding text over an image as this may not work with all email clients.

Don’t include file attachments or forms

These will be rejected. If you need the reader to look further, include a link to your company website, or a file sharing site such as Dropbox.

Are you one of the 52% or the 48%?

Following these guidelines won’t stop your email from being spam. That will depend on the content you are circulating. It will, however, increase your chances of bypassing the spam filters and getting into an inbox. What comes next is down to your writing – if you have caught the recipient’s interest they will open the email.

Catching – and holding – their interest for long enough to read the email is the harder part. The content has to interest them which means using the right language and introducing the topic in a way that engages them personally. As a salesperson or marketer, you already know this. So make your email personal, interesting and engaging. Don’t be one of the 48%.