Enter your keyword

Monday, 1 February 2016



Do your emails reach out to your subscriber’s inbox? Or they find their way to spam folder? Why an email lands to spam folder instead of user’s inbox? Let us try to understand some of the strategies that may help avoid junk filters of web-based email services, such as Google’s Gmail, Yahoo, Hotmail, Microsoft’s outlook and others.
                                     Avoid Email Spam Filters: Best Practices
Before moving forward let us understand few basic concepts.

What is SPAM

There are many definitions available but in simple words, any unsolicited, irrelevant email normally sent in bulk to a large list of people falls in the category of spam. It may be an attempt related to advertising, phishing, malware spread and show you great prospects of your business or an irresistible offer or lottery win or similar activities.

SPAM Laws and Guidelines

Most prominent law pertaining to spam is CAN-SPAM ACT of 2003. If you are sending emails to your users (sales or promotional content or otherwise also), these are few requirements of CAN-SPAM act, you must comply with:
  • Always use NON-DECEPTIVE ‘From name’, ‘reply-to-address’ and ‘subject line’.
  • Headers must not be false or misleading.
  • Always provide an unsubscribe link (user should be able to unsubscribe in a single click)
  • Unsubscribe link must not become dead for at least 30 days since email is sent.
  • Your physical address must be included in the email body.
If you however are sending a transactional email, you are exempted from these rules.
Since, Gmail is one of the major email service providers you may also want to explore Google’s bulk sending guidelines. This helps you identify the inbox categories in which your email may finally fall into. It also talks about the Additional guidelines for IPv6 such as Subscription, Unsubscribing, Format, Delivery, Third-Party Senders and Affiliate Marketing Programs.

Spam Filters: How likely an Email is a Spam

Spam filters check against number of criteria to determine ‘spamminess’ of an email.  Based upon number of factors a ‘spam score’ is assigned to an email. If email campaign’s spam score crosses the threshold, your email email falls under the spam category and lands in the spam or junk folder. Be aware that passing score is not universal and is different for individual servers so your email campaign may pass one spam filter but not necessarily all the filters.
SpamAssassin lists out few sample criteria (criteria are not made public since spammers will make use of those in their benefit to spread spam):
Talks about lots of money (.193 points)
Describes some sort of breakthrough (.232 points)
Looks like mortgage pitch (.297 points)
Contains urgent matter (.288 points)
Money back guarantee (2.051 points)

Major Reasons: Why Emails are Marked as Spam?

Here are few major reasons that point out the major reasons leading an email into a spam or junk folder.


Common content related mistakes that lead your email into junk folder are:
  • If your emails contains ‘Trigger Words’, or ‘phishing’ and ‘spammy’ phrases like, “CLICK HERE!!!”or “Never Miss this Lifetime Opportunity!!!” or “FREE, Buy Now.”, it is very likely that your email will land into spam folder.
  • You use too many colored fonts (bright colors).
  • You send inappropriate content.
  • Half baked html, such as using automatic converters from Microsoft word to html.
  • Too many images (general rule of thumb is at-least couple of lines per image). Sending one large image with no text is a bad idea making spam filters think you can trick them.
  • You do not include text version of your html emails (common mistake with new entrants).
  • You send large attachments or inappropriate attachments.


If an email is linking to blacklisted websites, it is more likely to be land into junk folder. Also DO NOT FORGET to put unsubscribe link in your email. User should be able to unsubscribe in a single click.

Email Source

Guilt by Association: if you send emails from the server that originates spam then your emails (specially to new subscribers) are very likely to be marked as spam. Shared hosting servers always risk this. Even if it was someone else using the same IP address, you pay the price.
Also to comply with CAN-SPAM Act you must add your physical address in the email body.


If your email contains false headers or mischievous header information, incorrect “From” or “Reply To” addresses, you guess it right, its an email’s way to junk folder.

User Engagement

You shall not send emails to INACTIVE users (who no longer open your emails). User engagement is one mammoth criteria of judging emails and unless users show interest in your emails, it is considered unwanted leading its destination to junk folder. Permission generally goes away in six month so ask users to reconfirm before sending them mails.
Many service providers including Gamil, Yahoo, Hotmail etc using this criteria to determine is your email should be delivered to inbox or spam folder.

11 Best Practices to Avoid Emails from Landing into Junk Folder

1. Use Double Opt-in Method for Subscription

Subscribe users using double opt-in method. in this
  1. method user fills a form on your website and provides email address.
  2. you send an confirmation link to the email address provided asking user to confirm his subscription by verifying his/her email
  3. if they click on the link, they are subscribed
  4. if they do not click on the link, they are no subscribed

2. Comply with CAN-SPAM Act

Do not send deceptive headers, ‘from’, ‘reply to’ information. Always provide single click opt out unsubscribe method and mention you physical address in the email.

3. Use Permission Marketing

Ask users to add your email to their whitelist. This is asking for users permission for sending them emails.

4. Keep Track of Engagement Metrics

Keep Tracking if users are opening your emails or not. Request them to open your emails. Ask them to check their spam folders if they do not find the mail inside their inbox and request them to mark it as NOT A SPAM. If users have not opened their email for over 6 months ask to reconfirm their choice of receiving emails from you.

5. Allow Users to Unsubscribe: Quick and Easy

Make one step process for users to unsubscribe from your email campaign. If people can;t unsubscribe easily they are more inclined to mark your emails as spam in order to avoid seeing them. This is also a mandatory requirement from CAN-SPAM act.

6. Use Spam Checkers Before you send Emails

There are free spam checkers available that you can use before making your email campaign live. SpamAssassin is one tool that can be installed on your desktop, where you can provide text input and look for SPAM check.
If you don’t like the idea of downloading a software, you may use IsNotSpam.com. To use form based solution use: ProgrammersHeaven.com

7. Do NOT use Blacklisted Server

Make sure your email server is not blacklisted else it will become increasingly difficult for you to reach out to new users. You may use following freely available websites to find the blacklisted servers.
If your server happens to be on the blacklist, do contact the websites/users that have marked you in the blacklist.
One of the ways to earn back reputation is to ask users that they mark your emails as NOT A SPAM.
You may also need to get a dedicated IP address and personal domain for email purposes, since any suspicious activity on your IP will get your emails delivered to junk folder even though it was not from you.

8. Check content of Your Email

  • Avoid phishing phrases, and inappropriate content.
  • Use proper ration of ‘text to image’.
  • Do not put blacklisted links.
  • Use properly formatted html.
  • Include text version of html emails.
  • Avoid too much use if flashy colors such as bright red or green.

9. Test with SPAM Filter

Once you are done with email application and ready to send emails to your clients, it is in your best interest to send first mail to yourself and copy raw mail with headers in a file test against SpamAssasin’s spam check. Look for the warnings and work upon them to be on the safe side.

10. Avoid Large and Inappropriate Attachments

Since spammers attach malicious and large attachments, avoid doing the same. Services such as Gmail, Yahoo, Hotmail etc. are more likely to have difficult time analyzing your attachment properly and thus chances your email landing into spam folder will only increase. If you need your users to have some attachments, try putting a publicly accessible link from where they it can be downloaded.

11. Set up your DKIM, SPF, Sender-ID, and Domain Keys Properly

In order to support email related protocols, you should take care of the following points:
  • Get at-least 1024 bits long Domain Keys or Domain Keys Identified Mail and stay safe from the risk of mail spoofing. Make sure it is properly implemented usingIsNotSpam.com’s free checking service. This helps ISP’s identify your authenticity from technical point of view.
  • Know more about this:
  • Have a valid A record other than a CNAME.
  • Full name of your mail host (set-up as an A record) should be set to your MX record.
  • Having done everything, verify your settings. dnsstuff.com is one such place to do your stuff.
  • For plain text emails, make charset in the ‘Content-Type’ header to be ‘ISO-8859-1’. Gmail pays close attention to this detail.

Final Thoughts

By now you would have known that there are number of things that are to be taken care off. If you can take care off such issues you may implement email server by yourself. It is however recommended that you have a dedicated email marketing service providers such as mailChimp. These dedicated platforms take care off these technical concerns and save you from getting blacklisted and lose your reputation.

No comments:

Post a Comment