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Spam Filters and User: It’s time to get to know each other better



Spam Filters

I think it’s high time to add “importunity” to the canonical list of mortal sins of contemporary marketers. Of course, I mean spam emails — undesirable guests in your inbox, the intentions of which are not as friendly as it might have seemed for the first look.

Time goes by, methods of spammers are getting more sophisticated, and their opponents – spam filters daily gain new methods of fighting unwanted email. But what should ordinary users and peaceful marketers do? It is not a secret that in the course of these confrontations,  advertising email campaigns of honest marketers suffer.

In order to protect yourself from persistent spammers and prevent your email campaigns from getting into spam, you should know all the details of the filtering process.

So, let’s get to know each other better!

What is spam filter?

It is a piece of software that uses sophisticated algorithms to protect you from unsolicited and unwanted incoming email. The main purpose of it is filtering your email correspondence for spam, based on special criteria.

You may be dissatisfied with their anti-spam policies. Due to aggressive filtering, deliverability of emails suffers and your carefully prepared and expected email campaign falls into spam. But at the same time, these automated programs serve day and night to protect people from multiple attacks of “shady” emails that can harm our well-being.

What threats does spam filtering protect us from?

Let’s start with a simple one, according to the researches made in far 2011, a person spends about 30 minutes per month on spam cleaning, and today this time has increased significantly. Spam is sent through all available communication channels: bulk SMS, mass mailing, social networks, messengers, post etc.

Depending on the country, from 50% to 80% of email traffic is spam.

Kaspersky Spam Report

Percentage of spam in global email traffic, Q2 2017 and Q3 2017

Because of spam, American business loses $22 billion million a year, Russian – $500, European — €51 bln.

The damage of spam

TOP 10 countries by percentage of users attacked

According to FBI estimates, the damage from Nigerian phisher activity from October 2013 to May 2016 exceeded US$3 billion and the number of affected companies was as high as 22,143. Those companies are scattered across 79 countries of the world.

Еxamples of spamming attacks

  • Via SMS messages:
    Spam via SMS
  • Via messengers:
    Spam via messangers
  • Via social networks:
    Spam via social networks
  • Via email:
    Spam via email

The last, but not the least is one of the most common and dangerous ways of spamming.

Basiсs methods of spam filtering

The principles of spam filtering

Depending on the degree of human involvement in the process,  spam filtering can be:

  • automatic – based on sophisticated algorithms of self-development and education;
  • non-automatic – parameters of which are set by a person and require constant updating.

Of course, the first method is the most common, since its effectiveness reaches 97%.

Automatic filters check emails by a list of certain criteria:

    1. Filtering the content of the email campaign. Such programs look through the content of the message and determine if it is spam or not. For this purpose, statistical analysis applies and certain special training is necessary. Based on hand-sorted emails, program learns to distinguish the content of good emails and of spam. This method is very useful for analyzing ad messages in the form text or HTML-emails. Depending on the size of training database, content filters can defend your inbox from 95-97% of spam.
      Weakness: The effectiveness of protection drops when the body of the message contains arbitrary text or text in the form of an image. For further analysis of such cases, the “report spam” button is to be used. Gmail’s filtering method is close to this.
    2. Sender name check. Filter stops all incoming emails from the addresses added to the spammers’ blacklist. The system sends the request through the DNS service and based on it response determines whether the IP is on the blacklist or not.
      Weakness: Spammers find new servers for their purposes as fast as their addresses get blacklisted.
    3. Subject line filtration. Programs used for email spamming are not so perfect either. For example, these programs can’t create the email header, according to the standard requirements (for example, these programs put spam trigger words in the subject line, don’t use personalization, make it too long. etc.).
      Subject line fitration
    4. Analysis of email attachments. Most often, such attachments are “.doc” files and images with certain text. The program filters images/text embedded in various file-type attachments. This technique provides almost complete safety from unwanted emails.
    5. Email header check.
      Email header check
      The header of junk emails includes information about the transfer of the email between the sender and the receiver. System analyses tags of the message: sender’s address, IP, the presence of all required tag-elements.
    6. Determination of mass character signs. In a huge stream of email messages, the system detects identical, or slightly different messages. This technique is mostly used in e-Commerce.
    7. Greylist check. The method of gray lists is based on the analysis of the “behavior” of software created for email spamming. All previously unknown SMTP-servers are marked as “grey” by the system. Messages from such servers are not accepted, but are not rejected completely – they get a temporary error code. If the sending server repeats its attempt after a certain period, the server is added to the whitelist if not  — to the blacklist.

Staying Away from Spam Filters in 2018

  • Test it for spam by yourself!
    Many of bulk email services and mailing applications have built-in spam checkers. Just run your email copy through it and see your score. Reduce the number of spam signals and your delivery rate will increase. You can use for this spam-checkers of Atomic Mail Sender.
  • Make sure that subject line = content
    Well, misleading subject lines are probably one of the worst mistakes you can make. Make sure your subject line is extremely related to a subject line.
    Spam survey from ISTR 2017

Also read about the Email Marketing Techniques of Avoiding SPAM-Words.

Spam survey from ISTR 2017

Source – Internet Security Threat Report 2017

  • Check the subject line
    Special characters in the subject line are real signals for a spam filter. Make sure your subject line looks clear and informative, and don’t use all kinds of -==TEXT==-, or $$TEXT$$, etc.
  • Watch your tongue
    Basic spam-filter triggers are keyword-oriented, this means spam-filters check your message and especially subject line for more spam-related keywords. Avoid using the pharmacy, finance, work-from-home, sale-related words. Use more neutral language and let it sound clear.
  • Valuable content
    What do you think –  is your content valuable and interesting? If not, then fix this as quickly as possible, because there is a high possibility for such content to be reported as spam, and this is the straight way to spam folders and blacklists. Try to provide your users with the most relevant content you have, so they forget about unsubscribing and spam-reporting.
  • Trust and respect
    Gain your recipients’ respect and trust. Ask them to add you to the whitelist, allow images from you and add you to contacts. This is the best honor you can get, besides sales of course.
  • Choose wisely!
    When you are using mail services make sure their IPs and SMTPs are whitelisted and trusted, also make sure they follow CAN-SPAM act rules. When you are using email software don’t buy SMTPs on forums and try to avoid sending large amounts of emails through free email service providers like Gmail, Yahoo, Hotmail, etc.
  • Register IPs you send from
    Ask your email marketing service to provide you with their sending IP addresses and register them as your own. Where do you do this?
    http://www.Openspf.org
    http://www.microsoft.com/mscorp/safety/technologies/senderid/default.mspx
  • KISS or Keep It Simple Stupid
    Make your HTML look simple, and don’t overdo it. Keep it like less than 50% of the message. Spam filters don’t trust complex HTML messages and will not always let it into recipients’ inbox folders.
  • Linking
    Make sure all your links look correct, images have proper links (not too long), titles, and alt-texts. Always link to an http:// domains, not an IP-address-domains.

What’s in the end?

Even if your email messages are perfect in all respects, there is a risk of being blocked by spam filters. So, to prevent that, we should know the code of anti-spam knights well enough in order to avoid spammer status and also to help them protect the peaceful user from the legions of dark spammers.

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Written by: Anastasia Sukhareva