Why Do Cold Emails Need Anti-Spam Filtering Serviceby@dmytrochervonyi
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Why Do Cold Emails Need Anti-Spam Filtering Service

by Dmytro ChervonyiJanuary 17th, 2020
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Up to 90% of businesses who rely on cold emails find out that their emails have been marked as undesirable content even though their recipients hadn’t yet gotten to see their message before it was deleted. Google Spam Filter is very strict towards every message that has no direct purpose and cannot distinguish itself from shady content. Hard bounces occur when emails are sent back by your recipient’s email service provider, or when your Sender Score is reduced to negative, little can be done.

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Anti-spam campaigns and anti-spam monitoring are essential parts of cold email and marketing campaigns.

Why lead generation involves dealing with spam 

As we know, spam is a bulk of advertising emails that nobody asked for. 

But up to 90% of businesses who rely on cold emails find out that their emails have been marked as undesirable content even though their recipients hadn’t yet gotten to see their message before it was deleted.

What they’re dealing with, is the echoes of 2006-2011 in the era when the world of online was new to all of us, yet some persons were determined to exploiting the latest technology and become an endless source of frustration to anyone with an email. 

Around that time, anti-spam filters were introduced into our email-sending routine to help the users manage with the flow of annoying emails that are irrelevant to their needs. 

One of the most well-known and massive filters is Google Spam Filter.

This is the filter we work with most often. Integrated with every Gmail mailbox owner sending routine, Google Spam Filter is very strict towards every message that has no direct purpose and cannot distinguish itself from shady content.  

Since outreach campaigns involve sending emails to the users who haven’t heard about us, we fall under the Google Spam Filter’s radar despite the fact that our emails are sent to well-researched, validated prospects whose needs align with our assets. We never reach out to someone who is potentially not interested in our services, and our task is to convince Google Spam Filter to differentiate us from the bad guys. 

How we do it

Our work involves lots of monitoring. We keep a close eye on the following indicators: 

Sender Score

It defines your mailbox’s status and whether it got labeled as spammy. Your email reputation score can be negative (-), positive (+), and spam (X).  The difference between (-) and (X) indicators is that (X) is a subdivision of (-). Each new mailbox starts with a 0 score and can send up to 30 to 40 emails. 

You can influence your Sender Score by yourself if you know the ways to tweak it.

Positive activities

  • Not exceeding the daily quote
  • Responding to incoming emails
  • Opening emails
  • Marking emails as important
  • Making pauses between sending
  • White-flagging emails marked as spam

Negative activities

  • Exceeding the daily quote
  • Labeling emails as spam
  • Removing emails without reading
  • Getting emails bounced
  • Sending generic emails
  • Sending emails in bulk without pausing

As your positive activities increase the rating, the average email quote grows from 50 emails to 250 and more emails. Harmful activities result in your score dropping down to (-) and even to (x), so more, and more of your emails end up in spam folders or also blocked by the email service provider.

Note that if your Sender Score is anywhere in the spam zone, it still can be recovered. However, if it’s reduced to negative, little can be done.


We all know what bounces are — they are emails blocked or sent back by your recipient’s email service provider. However, another thing you should know is that there are different types of bounces. To see that difference and to monitor every kind of bounces is essential for preventing your emails from going deeper into the spam pit. 

Soft bounces

This is the harmless type of bounces that occurs due to the temporary issues on the recipient’s side. For instance:

1. Full inbox.  The recipient has exceeded its quota of incoming emails, so there is no space left for your message.

2. Email server down. Your email wasn’t delivered due to server maintenance or server connection problems.

3. Oversized email. Your email is too large, so you need to reduce the volume of characters or remove attachments that add extra weight.

Hard bounces

This is the worst type of bounces. The one that won’t be fixed with time and the one that will drag your domain rating down to the point of no return. Hard bounces occur when:

1. Email address is invalid or doesn't exist. Your recipient no longer uses the address or the address in your database is incorrect.

2. A domain name is incorrect or doesn’t exist. Your email was sent to a non-existing domain.

3. Delivery is blocked by the email server. Your domain rating went down to the contrary, and now the email service provider prevented you from sending messages entirely.

When we know what kind of data to look out for, we know how to work with Google Spam Filter by maintaining positive activities on our mailboxes and performing day-to-day monitoring. 

However, aside from Google Filter, there are also such filters as Spam Assassin and Barracuda. These are the second most wide-spread spam filters that every sender should be aware of and the filters we deal with as we help our customers. 


  • Barracuda has a robust set of technologies purposed for malware protection and preventing harmful traffic.
  • This filter is designed to ensure that all security protocols are in place and isolate potentially dangerous senders from the recipients.
  • It’s mostly a security solution, so don’t use your regular mailboxes as business mailboxes and have an expert to take a close look at your protocols to ensure all of them are valid. You can see how it’s done here.

Spam Assassin

  • Spam Assassin is a filter heavily oriented towards content. It is designed to find spam triggers in the headers and the content of incoming emails.
  • The filter uses a point system to evaluate each email’s spam status. The moment there are more than 5 points, the email gets labeled as spam.
  • Additionally, Spam Assassin scans the address of the sender, address of the recipient and checks whether the email corresponds with all the standards.
  • To spare yourself from being labeled as spam by this filter, make sure to check and proofread your messages before sending them and keep the list of the known spam triggers close at hand.


In my practice, it’s better safe than sorry — especially when you work with tons of emails.

Services that can help detect that are you in spam:

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