Poor Email List Alert: Guide To Spot & Remove Spam Sign-ups

Poor Email List Alert: Guide To Spot & Remove Spam Sign-ups

Dan Zinoviev
Apr 25, 2023
Reading duration
17 min

Did you know that the number of global email users is aimed to hit 4.6 billion users by 2025? Such meteoric rates seem promising to those involved with email outreach. Every shiny new email address on your mailing list can be a treasure trove, boosting your company's ROI to dazzling heights. ✨

But beware! A healthy mailing list concerns active email addresses, while inactive or phony ones are sneaky troublemakers. They can wreak havoc, causing plummeting email deliverability and open rates, soaring bounce scores, spam complaints, and — the horror! — killing your email sender reputation excellence.

22.71% of an email list goes bad every year… and add the number of fake signs ups to this data to understand the real danger to your email deliverability. Invalid, misspelled, and unengaged emails can bulldoze all the marketing efforts put into the campaign.

Before you start panicking, Folderly experts have your back, armed with top-notch tactics tested in practice to detect, eliminate, and prevent those pesky fake sign-ups from invading your mailing lists.

Ready to join us on our anti-spam sign-up crusade? 

Let’s dive in.

The Article Walkthrough:

How Do Fake Sign-Ups Hurt Your Email Deliverability?

It's utterly easy to let the fact that sign-up details affect your marketing campaign slip if you don't know how they impact your deliverability scores.

Your emails will go to spam

Nearly 85% of all emails are spam. Even sending genuine, user-oriented, and helpful content, hitting the wrong user may send your campaign flying into the spam folder (even if you are a guru of how to send mass email without spamming). How does this relate to fake sign-ups? Simple.

As fake addresses infiltrate your mailing lists, people who have never heard of you and never considered signing up for your services will see their mailboxes flooded with your messages. What is your primary instinct when you spot a message from an unknown sender, no matter how legit it may look? The answer will be to either delete or mark as spam.

Your metrics will be misleading

As more and more spam sign-ups infiltrate your mailing list, the metrics will start to deviate, all due to spam contacts not engaging with your emails.

For instance, you may notice your open rates or click-through rates (CTR) drop. Assuming that there's something wrong at your end, which is partially true, you will start experimenting with your content, price policy, or even services on offer. The interaction will bring little progress because you are barking at the wrong tree.

You won't have an accurate image of your customers

While altering the e-commerce analytics, fake sign-ups will also negatively impact the general user image. Determining what makes your clientele tick is nearly impossible since many aren't natural. 

For example, you've centered all of your marketing efforts on one location – let's say the USA – and then you notice that people start to sign up from the UK. As you start to adapt your strategy to a new client base (the fake one), you may lose the actual audience in the process.

Your domain reputation will be damaged

The tricky part about your domain reputation is that it relies on multiple pillars, while a single issue like spam sign-ups may ruin it at the speed of light. Fake sign-ups can affect you in several ways:

  • Spam complaints – your messages target people who aren't into your services, and they will mark you as an ultimate source of spam, decreasing your deliverability scores.
  • High bounce rates – inactive and fake email addresses will make your sent messages bounce since they can't be technically delivered. Most Email Service Providers (ESPs) react negatively to such statistics too.
  • Blacklisting – the lower your domain reputation gets, the more suspicious ESPs will get until you end up on one or several blacklists. It's almost impossible to target users' primary inboxes from Spamhouse blocklist or other major blacklists.

For fairness' sake, email deliverability tools like Folderly will help you detect and fix potential deliverability issues. Still, you must know how to identify spam sign-ups and eliminate and prevent them.

5 Types of Fake Spam Sign-Ups

Before you embark on your quest to vanquish spam sign-ups, you must learn to recognize their many faces. These pesky villains can be sneaky, making it twice as challenging to spot them in your email campaigns. So, here is the overview of different types of fake sign-ups (including the non-obvious ones): 

Malicious Spambots 🤖

One of the known ways to grow your mailing list is to spice up your platform with a sign-up form that comes in different shapes and sizes. As helpful as the form is, there’s a high chance it will attract spambots.

Spambots are specially written programs to spot your sign-up form and pollute it with inactive or irrelevant email addresses. Barracuda network reports show that spambots make up 66% of all internet traffic, with vicious bots accounting for 40%.

Why do spammers go to these lengths? There are a few potential reasons:

  • They look for a weak spot in your website to use it for personal gain;
  • They want to access your active email address database to use it for spam;
  • They aim at ruining your marketing efforts altogether. 

While a few fake sign-ups won't send you straight to the blacklist database, as they keep piling up, your email deliverability rates will start to suffer, bringing most email outreach efforts to zero. There are several proven practices we'll discuss later to eliminate spam sign ups for spambots.

Disposable email addresses

Disposable email addresses serve as temporary accounts that people can use for various purposes. Usually, such addresses remain active for a limited time and then get deleted.

With an ever-growing focus on privacy, disposable email addresses are becoming increasingly popular. This trend became apparent when Apple introduced the "Hide My Email" feature in iOS 15.

Indeed, disposable email addresses do have their merits. They empower users to manage the influx of marketing communications by filtering, isolating accounts, or simply deleting them—mainly when there's uncertainty or mistrust. A type of disposable email address is email aliases.

But regarding your email deliverability—it’s another lousy type of sign-up.

Let’s review three types of disposable email addresses:

😐 Aliases (not so bad) 😔 Forwarding account (worse) 😭 Non-Forwarding Throwaway Account (the worst):

A variation of a genuine email address, hosted by the user's inbox provider, like Gmail or Outlook. Messages sent to an alias are delivered to the user's inbox but can be filtered to a folder separate from the primary inbox. 

These addresses remain active until the user deletes them. 

And you never know when it will happen.

Check the full guide on email aliases to learn more.

Such disposable email addresses are created on a different domain from the user's primary email account and forward messages to that account. 

These accounts also stay active until the user deletes them, but you may not receive accurate open or click data for the emails sent to them.

These are typically one-time-use email addresses created on a different domain, like "F-143rz6ierfwr3424a@maildrop.cc". 

They're the stuff of email marketing nightmares, as they hard bounce after the first send and provide no value to your database.

As most individuals use disposable email addresses to access all sorts of freebies your business provides, they will clutter your mailing lists. After the person deletes their temporary address, it will cause your outreach messages to bounce.


Emails from purchased lists

Even though purchasing or renting mailing lists is against the anti-spam CAN-SPAM Act, some businesses ignore that fact. Assuming that extended email lists will trigger easy leads, vendors forget that most addresses on those lists are compromised, inactive or non-consented.

What happens when you send your cold emails to invalid or unengaged email addresses? They will lead to spam sign-ups driven to ruin your email marketing campaign through high spam complaint rates, high bounce rates, and dropping sender reputation scores.

Human-generated fake email addresses

In addition to disposable emails created via online services, you must also be cautious of human-generated fake email addresses. Creating these phony email addresses is deceptively simple. They consist of various combinations of letters, symbols, and numbers and often appear legitimate but don't belong to real users:


When such addresses sneak into your mailing list and accumulate, they can cause some severe headaches. Your hard bounce rate will soar, as messages can't be delivered to non-existent mailboxes.

Stolen or compromised email accounts

Phishing attacks are more common than you think. Around 3.4 billion phishing emails are sent globally daily. Once an email address gets compromised or stolen, it can be used to infiltrate your mailing lists instantly.

Stolen and compromised email accounts are often used for spam sign-ups. It's essential to stress the importance of the issue so that you take adequate precautions against it:

  • Loads of spam content piling in the owner's mailbox will make them consider switching to a new, more secure account. While it's a wise decision, it may rid your mailing list of another potentially active subscriber.
  • Every compromised email will hurt your sender's reputation.
  • Stolen email accounts put sensitive user information at risk.
  • Potential legal consequences.

And this is not an exclusive list. Cybersecurity threats and vulnerabilities across the online world constantly take on new forms and shapes. It makes sense to regularly check trusted sources with cybernews to stay one step ahead of new forms of spambots. 

Are You Prone to Spam Email Sign-Ups? Check With These Questions

It's hard to say for sure, but answering the following questions can help you determine if your email list is prone to fake sign-ups. The more 'yes' answers you have, the higher your risk of being targeted by fake sign-ups:

☐ Does your newsletter subscription lack reCAPTCHA or other safety measures for protection?
☐ Do you have a prominent online presence with high traffic?
☐ Do you offer coupons and various freebies for every new sign-up?
☐ Do you use a single opt-in sign-up confirmation form?
☐ Is your sign-up form limited to a single-confirmation method (without test questions on the list)?
☐ Do you procrastinate trying the honeypot sign-up field?
☐ Does your sign-up form miss out on a properly-configured time-analysis filter?
☐ Do you allow multiple sign-ups from a single IP?

Bad news: if you answered “yes” to at least three of these questions, the chances are your email list is filled with fake sign-ups.

Good news: By evaluating your email marketing practices with these questions, you can identify areas for improvement and better safeguard your email list from spam sign-ups!

So, let’s get started.

8 Ways To Identify Spam Sign-Ups

There are 7 main methods to detect fake sign-ups. Let's look closer at them:

1) Look for queues in the email address

Some fake sign-ups stand out from the other addresses since they look as spammy as possible. Thus, when inspecting your mailing list, the first thing to do is pay attention to the provided textual data. Once you spot these patterns, it's time to clean your mailing lists:

  • Emails with random strings of characters. For example: bujhg52r59f@domain.com 
  • Similar-looking emails. For instance: janedoe1@domain.comjanedoe2@domain.com and janedoe3@domain.com 
  • Disposable emails. Not all disposable email addresses are illegitimate and spam-oriented. Yet, every time you spot an email with mailinator.com or guerrillamail.com in large quantities on your mailing list, it's advised to double-check the issue.
  • Emails containing countless numbers. Like joe26979579@domain.com
  • Numerous emails sharing the same domain or IP indicate a potential fake sign-up.

2) Verify the email address domain

Spam sign-ups are often connected with unreliable ESPs. You can easily spot intruders and eliminate them from your lists by checking the domain.

  • Extract the domain you doubt. The domain name is what comes after the @ part.
  • Carry out a DNS lookup. Services like MX Toolbox will tell you if the domain is valid.
  • Check the validity of MX records.

3) Use email verification tools

Email verification tools allow you to check a large list of emails for accuracy quickly. It's a great app to ensure an email is valid and accurate. Some of the email verification tools to consider are: Zero Bounce, Snov.io, GetEmail.io, DeBounce, Clearout.


4) Look for the geographic location

Another practical way of identifying spam sign-ups would be to watch out for an unusual spike in subscriber rates from countries you don't advertise to. Also, it's advised to track whether a potential subscriber shares the same country that their IP address is connected to.

5) Monitor user behavior

If there's one thing certain about fake sign-ups, they aren't used for meaningful interaction with a business or service. Most spam sign-ups are created for scamming activities or temporary personal gain. Thus, a brief behavior analysis will give you an idea about the identity hiding behind a suspicious email address. A spambot will never go to the length of interacting with your website, platform, or blog.

6) Inspect sign-up frequency

We've established already that a rapid increase in sign-ups may potentially indicate a fake sign-up invasion. However, there are other sign-up frequency points to evaluate to finalize your opinion:

  • Simultaneous sign-up for all your offered services if you cover more than one field.
  • Immediate sign-ups: A human needs a few moments to fill out the required fields, while a bot does it instantly.
  • Frequent sign-ups from the same IP address.

Test the email address from another inbox. If you email the given address, and it bounces, the verdict is obvious – it is a fake sign-up to get rid of immediately.

7) Watch out for the corporate vs. private emails ratio

This may not come as one of the most obvious anti-fake sign-up practices, but it may help you out immensely. Let's say you're a vendor involved with a B2B field, and suddenly, your mailing list is flooded with private email addresses instead of corporate ones. This works the other way around, too.

8) Send email from another email domain

Finally, if any email is suspicious for you, although it looks like a real person—you can always check it by sending a message from your other email accounts. Just make sure it’s something useful, and the content doesn’t violate email compliance policies.

How To Remove Spam Sign-Ups?

Once you identify fake sign-ups that invade your email list, you must know how to deal with them effectively. Let’s review the best practices.

Manual inspection and removal

One of the most effective yet quite time-consuming options to eliminate spam sign-ups would be to detect and delete them manually.

As you've already identified spam sign-up patterns, you must divide your list into corresponding segments and eliminate the harmful intruders. 

Let's discuss the in-depth process with Campaign Monitor as the platform in use:

  1. Decide on the category to isolate the fakes. You can use the "Name," "Email," "Location," or "Date subscribed" fields to create a separate segment.
  2. Instead of deleting each address manually, we suggest you send it to the Suppression List instead. You can delete all the suppressed emails in bulk whenever you decide.
  3. With a new segment, you should proceed to the List & Subscribers field.
  4. Click Segments.
  5. Choose the fake sign-up segment.
  6. Click the Export Segment to download a CSV file with spam addresses.
  7. Go to List & Subscribers.
  8. Click Suppressions on the left menu.
  9. Click Add to Suppression List and paste the downloaded addresses from the chosen segment.Image6
  10.  Click Add to Suppression List again to save the changes.

Using email validation services

If you can afford to invest in a quality email validation service, it will be a fast and effective way to detect and get rid of fake sign-ups. Most validation tools present the service of list cleaning in addition to validation. For instance, ZeroBounce, Debounce, NeverBounce all offer list cleansing.

Monitoring and deleting hard bounces and unsubscribe requests

Manual and automated spam sign-up elimination is a more or less obvious way to keep your email list clean. However, there's another quite practical approach to the matter. You can monitor your list for hard bounces and unsubscribe requests.

While not all the hard-bounced emails and unsubscribe requests are actually fake sign-ups, deleting those whenever you spot them will help you keep your sending list clean and updated.

How To Prevent And Stop Fake Sign-Ups in the Future

Is it possible to safe-proof your email list so that no fake sign-ups can breach the defenses? Yes! Luckily, there's more than one way to prevent and stop fake sign-ups once and for good.


Target fake sign-up group: Chat Bots. 

One of the simplest yet most effective means against spambots is reCAPTCHA. This fantastic fraud detection tool developed by Google keeps your website bot-free and fun for everyone.

If you want to ensure that all actions on your website are performed by “real” people, not bots, and using an image puzzle query isn’t what you’re looking for, Google’s reCAPTCHA API solution is just the thing.

reCAPTCHA v3 monitors each visitor’s behavior to decide whether it’s a human or a bot. 

Why choose reCAPTCHA 3? 🤔

  • No more image puzzle queries (runs invisible to the user)
  • Continuously monitors user behavior and scores users
  • You can decide what to do based on scores (block or restrict access if a score is below 0.7)
  • It’s possible to add two-factor authentication for extra security

reCAPTCHA v2 ("I'm not a robot" Checkbox) passes users immediately or challenges them to prove they're human. Unlike reCAPTCHA v3, it can disrupt the user experience and is less secure than the newer version.


Add a double opt-in form

Adouble opt-in form will keep fake sign-ups at bay. The feature requires a user to confirm the initiated sign-up through the presented email. This means a user must go to their mailbox and approve the sent confirmation link — no bot can do that. Should you spot a sign-up that has failed the confirmation step, it must be deleted immediately.

Also, such an explicit opt-in is of utmost important for some ESP (For instance, without it, you may see your Mailchimp emails going to spam).


Use the "Honeypot Captcha" technique

This is the case when you set traps for spambots, and they are sure to get in. The basic role of the honeypot CAPTCHA is to lure bots in so you can easily detect and eliminate them from your lists.


Basically, a honeypot is a hidden field in the sign-up form that no human user can see. It is detected and subsequently filled out by bots and programs only. All it takes is to sort your lists by the hidden field and find all the spammers caught in the same place.

Use a third-party app

You don't have to fight this anti-fake battle on your own. It is possible to delegate the responsibility to a trusted app or extension effectively. Countless third-party apps provide additional security and verification. You may want to consider the following:

These are to name a few. You can mix and match different tools based on your needs and preferences.

OTP verification

One-time password verification (OTP) is a double opt-in at its core. The central role of the process is to create a one-time code and send it to the potential subscriber's email or phone number. It takes time to copy the code so that you can proceed with the sign-up. As you may have already gathered—no spambot can succeed with the task.


OTP verification ensures that only real users are added to your mailing lists. Aside from preventing fake sign-ups, OTP verification will help you keep fraud at bay so that no one can gain unauthorized access to your services.

Multi-factor authentication

Some people may view multi-factor authentication (MFA) as a somewhat restrictive measure since it takes time and effort for a user to get through it. While the approach may filter most potential subscribers, it will instead leave you with an incredibly involved and interested audience.

MFA links the email address with a phone number, so a subscriber must verify their identity through both. Some companies even use credit card authentication to restrict access to valuable free trials.

A variety of present-day platforms that offer MFA solutions are available for implementation into your online business.

Social login

One of the most effective ways to filter bots from your mailing lists is to implement social login verification. Basically, you'd be asking people to sign up for your services via their social media accounts, such as Google, Twitter, or Facebook.

This approach is so effective because platforms like Google carry out their checks before confirming user accounts, so you can be sure that you are dealing with real people.

Regular email deliverability testing

Last but not least, one more practical way to ensure that your email lists are free of spam sign-ups is to test your deliverability scores often. With the  Folderly's deliverability test, you can quickly check email domain deliverability and notice when the rates drop immediately.

As you start to investigate the matter, you will be inspired to double-check your recent subscribers in case the problem roots there. Even if that isn't the case, a timely test will help you save the campaign on time.

Don't Forget To Enjoy Unexpected Benefits From Tackling Fake Sign-Ups

There's always a way to derive something positive, even from such a grim situation as spam sign-ups.

As you start fighting back and spend time plucking out those spam sign-ups like unwanted weeds, you'll gain better insight into your target audience and email deliverability issues. When you know who's real and who's a scam, you'll focus your marketing efforts on those who crave your assistance instead of wasting your resources. And, besides, today's email outreach tools help to overcome any deliverability issues with ease.

Being transparent about your security measures shows your target audience that you genuinely care about them. Once you establish a trusting connection with your client base, you'll learn to suffice them without asking twice. Isn’t that a positive outcome?

Dan Zinoviev
Dan Zinoviev
Sales Executive at Folderly
With 5+ of experience with email outreach and deliverability, Dan has become a trusted advisor for customers seeking optimal email solutions. With comprehensive product knowledge, Dan drives sales by effectively bridging the gap between the product and customers’ needs.

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