Why Emails go to Spam and What do you do?

Why Emails go to Spam and What do you do?

According to statistics, 53% of all sent emails are spam. As a result, spam filters are becoming stricter, and even legitimate emails can end up in the spam folder. There are some steps you can take to ensure that all your emails are being delivered to the inbox on the recipient’s side. But first, let’s discuss what the spam filter is and how it works.

What is a Spam Filter?

A spam filter is a software that identifies and blocks potentially dangerous emails from entering your inbox by using a set of rules and algorithms.

How does the Spam Filter Work?

What a typical spam filter checks for can be divided into three categories:

  • Where does the message come from?

Anti-spam organizations have created special network lists, which are called RBLs (Real-time blackhole lists). Spam filter checks such lists for the IP address and the domain name that the message was sent from. If the IP address matches one on the list, the spam score of the message increases.

  • Who sent the message?

Use email headers spam filters to check if the email was sent by a spam engine or by a real sender. Every email has a unique ID, but when the spammers send mass emails, they all have the same ID.

  • What the message looks like

The spam filter analyzes the body and the subject of the email. Strings, that can be identified as spam are ‘buy now’, ‘lowest prices’, ‘click here’, etc. Also, it looks for flashy HTML such as large fonts, blinking text, bright colors, and so on. A lot of spam filters compare the whole text to the number of suspicious words. So, for example, if your email is long, it will not be identified as spam because of a few suspicious words. Below are examples of spam words:

This isn’t a scam, Earn per week, Mail in order form, Reverses, #1, Easy terms, Maintained, Reverses aging, $$$, Eliminate bad credit, Make $, Risk free, ‘Hidden’ assets, Eliminate debt, Make money, Rolex, 100% free, Email harvest, Marketing, Round the world, 100% Satisfied, Email marketing, Marketing solutions, S 1618, 4U, Expect to earn, Mass email, Safeguard notice, 50% off, Explode your business, Medicine, Sale, Accept credit cards, Extra income, Medium, Sales, Acceptance, F r e e, Meet singles, Sample, Access, Fantastic deal, Member, Satisfaction, Accordingly, Fast cash, Member stuff, Satisfaction guaranteed, Act Now, Fast Viagra delivery, Message contains, Save $, Act Now!, Financial freedom, Message contains disclaimer, Save big money, Act now! Don’t hesitate!, Financially independent, Million, Save up to, Ad, For free, Million dollars, Score with babes, Additional income, For instant access, Miracle, Search engine listings, Addresses on CD, For just $ (some amount), MLM, Search engines, Affordable, For just $xxx, Money, Section 301, All natural, For Only, Money back, See for yourself, All new, For you, Money making, Sent in compliance, Amazing, Form, Month trial offer, Serious cash, Amazing stuff, Free, More Internet Traffic, Serious only, Apply now, Free access, Mortgage, Shopper, Apply Online, Free cell phone, Mortgage rates, Shopping spree, As seen on, Free consultation, Multi level marketing, Sign up free today, Auto email removal, Free consultation, Multi-level marketing, Social security number, Avoid, Free DVD, Name brand, Solution, Avoid bankruptcy, Free gift, Never, Special promotion, Bargain, Free grant money, New customers only, Stainless steel, Be amazed, Free hosting, New domain extensions, Stock alert, Be your own boss, Free info, Nigerian, Stock disclaimer statement, Being a member, Free installation, No age restrictions, Stock pick, Beneficiary, Free Instant, No catch, Stop, Best price, Free investment, No claim forms, Stop snoring, Beverage, Free leads, No cost, Strong buy, Big bucks, Free membership, No credit check, Stuff on sale, Bill 1618, Free money, No disappointment, Subject to cash, Billing address, Free offer, No experience, Subject to credit, Billion, Free preview, No fees, Subscribe, Billion dollars, Free priority mail, No gimmick, Success, Bonus, Free quote, No hidden, Supplies are limited, Brand new pager, Free sample, No inventory, Take action now, Bulk email, Free trial, No investment, Talks about hidden charges, Buy, Free website, No medical exams, Talks about prizes, Buy direct, Freedom, No middleman, Teen, Buying judgements, Friend, No obligation, Tells you it’s an ad, Buying judgments, Full refund, No purchase necessary, Terms and conditions, Cable converter, Get, No questions asked, The best rates, Call, Get it now, No selling, The following form, Call free, Get out of debt, No strings attached, They keep your money – no refund, Call now, Get paid, No-obligation, They’re just giving it away, Calling creditors, Get started now, Not intended, This isn’t junk, Cancel at any time, Gift certificate, Notspam, This isn’t spam, Cannot be combined with any other offer, Give it away, Now, This won’t last, Can’t live without, Giving away, Now only, Thousands, Cards accepted, Great offer, Obligation, Time limited, Cash, Guarantee, Off shore, Trial, Cash bonus, Guaranteed, Offer, Undisclosed recipient, Cashcashcash, Have you been turned down?, Offer expires, University diplomas, Casino, Hello, Once in lifetime, Unlimited, Celebrity, Here, One hundred percent free, Unsecured credit, Cell phone cancer scam, Hidden, One hundred percent guaranteed, Unsecured credit/debt, Cents on the dollar, Hidden assets, One time, Unsecured debt, Certified, Hidden charges, One time mailing, Unsolicited, Chance, Home, Online biz opportunity, Unsubscribe, Cheap, Home based, Online degree, Urgent, Check, Home employment, Online marketing, US dollars, Check or money order, Homebased business, Online pharmacy, Vacation, Claims, Human growth hormone, Only, Vacation offers, Claims not to be selling anything, If only it were that easy, Only $, Valium, Claims to be in accordance with some spam law, Important information regarding, Open, Viagra, Claims to be legal, In accordance with laws, Opportunity, Viagra and other drugs, Clearance, Income, Opt in, Vicodin, Click, Income from home, Order, Visit our website, Click below, Increase sales, Order now, Wants credit card, Click here, Increase traffic, Order shipped by, Warranty, Click to remove, Increase your sales, Order status, We hate spam, Collect, Incredible deal, Order today, We honor all, Collect child support, Info you requested, Orders shipped by, Web traffic, Compare, Information you requested, Outstanding values, Weekend getaway, Compare rates, Instant, Passwords, Weight loss, Compete for your business, Insurance, Pennies a day, What are you waiting for?, Confidentially on all orders, Internet market, Per day, While supplies last, Congratulations, Internet marketing, Per week, While you sleep, Consolidate debt and credit, Investment, Performance, Who really wins?, Consolidate your debt, Investment decision, Phone, Why pay more?, Copy accurately, It’s effective, Please read, Wife, Copy DVDs, It’s effective, Potential earnings, Will not believe your eyes, Cost, Join millions, Pre-approved, Win, Costs, Join millions of Americans, Price, Winner, Credit, Laser printer, Prices, Winner, Credit bureaus, Leave, Print form signature, Winning, Credit card offers, Legal, Print out and fax, Won, Cures baldness, Life, Priority mail, Work at home, Deal, Life Insurance, Prize, Work from home, Dear [email/friend/somebody], Lifetime, Prizes, Xanax, Diagnostics, limited time, Problem, You are a winner! Dig up dirt on friends, Limited time offer, Produced and sent out, You have been selected, Direct email, Limited time only, Profits, You’re a Winner!, Direct marketing, Loans, Promise you, Your income, Discount, Long distance phone offer, Pure Profits, Do it today, Lose, Quote, Don’t delete, Lose weight, Quotes, Don’t hesitate, Lose weight spam, Real thing, Dormant, Lower interest rate, Refinance, Double your, Lower interest rates, Refinance home, Double your income, Lower monthly payment, Refinanced home, Drastically reduced, Lower your mortgage rate, Removal instructions, Earn, Lowest insurance rates, Remove, Earn $, Lowest Price, Removes wrinkles, Earn extra cash, Luxury car, and Reserves the right.

NOTE: This list is not all and is just an example of some spam patterns. They can constantly change due to the spammers adjusting to the new restrictions on the side of spam filters.

How to Improve Your Email Delivery

There are several things you can do to improve your email delivery Change to Basic requirements for the creation of a valid email:

Valid Sender Information:

  • Use a recognizable and legitimate sender email address. Avoid generic or suspicious sender names.
  • Ensure that the “From” field accurately represents your organization or brand.

Clear Subject Line:

  • Write a subject line that reflects the email’s purpose concisely.
  • Avoid misleading or clickbait-style subject lines.
  • Do not end a subject with a question mark or space.
  • Do not use only uppercase letters.
  • Do not use the words like Test/Testing in the subject.

Structured Email Body:

  • Organize your email content into paragraphs or sections.
  • Use headings, bullet points, and numbered lists to improve readability.
  • Do not use the introduction at the beginning of the email.
  • Do not use too many special symbols, especially at the beginning or at the end of the sentence.

Signature and Contact Information:

  • Include a professional email signature with your name, job title, and contact details.
  • A well-formatted signature adds credibility to your email.

Avoid Excessive Links and Attachments:

  • Limit the number of hyperlinks in your email.
  • Attachments should be relevant and necessary; avoid overloading the email with files.
  • Be careful with the images. It is recommended not to send emails with images only. Make sure you have no less than two strings of text in every image and your images are optimized.
  • Do not use shortened URLs. Those are often used by spammers to hide their real URLs.
  • Avoid some types of attachments like .exe, .zip, .swf. It is okay to use .jpg, .gif, .png and .pdf.

Unsubscribe Option:

  • The email should be identified as an ad if that is what you are sending.
  • Include an easy-to-find unsubscribe link. Compliance with anti-spam regulations is crucial. Honoring unsubscribe requests builds trust with recipients.

Plain Text Version Alongside HTML:

  • Some email clients may not render HTML properly. Including a plain text version ensures accessibility for all recipients.
  •  Avoid different colors of fonts, if possible.

Domain Configuration:

  • Check SPF and DKIM records. Sender Policy Framework (SPF) records allow domain owners to publish a list of IP addresses that are authorized to send emails on their behalf. The goal is to reduce the amount of spam and fraud by making it much harder for malicious senders to disguise their identity. Domain Keys Identified Mail (DKIM) helps you protect your company from email spamming and phishing attempts. It provides a method for validating a domain name identity that is associated with a message through cryptographic authentication.

Other recommendation:

  • Do not purchase email lists. It is a common practice to purchase lists of potential clients. However, a lot of email addresses in such lists are not correct and your IP/domain can get blacklisted for mass mailing very fast. It is better to send individual emails to real people.
  • Check how your emails are delivered. You can create different email accounts with popular email providers like Google, Yahoo, and so on, then send test emails to them.
  • Send the emails to your clients regularly and instruct your recipients on how to whitelist your email address.

Why can Spam be Delivered?

Although anti-spam systems are quite advanced nowadays and should block about 90,9% of spam emails, it’s important to note that no system is perfect enough to block 100% of spam emails for all users (at least for now). When an email containing spam is incorrectly identified as a legit one and is delivered to Inbox it’s called a false negative. For example, links that appear to be of familiar websites, but in fact, lead to phishing websites. What factors contribute to getting false negatives?


  • A new spam pattern that is not known to the system yet: Since most anti-spam filters use machine learning technology, they constantly learn on the go, meaning that new spam patterns are added to their database for identifying such emails and blocking them. At the same time, spammers do this as well. When they constantly try to adjust to new realities to deceive anti-spam filters, they create new patterns that systems may not identify at once.
  • Subjective content filtering: In some cases, content filtering may get tricky. Where some things are easy to identify, email content is not black and white. Of course, there are known indicators of spam and blocklisted domains. TLDs that are used for sending spam, execute file attachments, or known spam keywords contained in the email. However, content guidelines for spam are always changing, much like our world. That’s what makes it difficult sometimes for anti-spam systems to distinguish whether some email is spam or harmful.
  • Users may have different opinions about what is considered spam: The definition of spam can be subjective to most recipients. Some refer to it as simply unwanted communication (including legitimate advertisements that they no longer wish to receive) even if such emails don’t possess spam factors.

That’s it!  Feel free to contact us if there is anything we can assist you with.