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Should I Worry If Email I Send Is Marked as Spam?


A business I was working with told me that they ‘sent my email address to spam’ because they didn’t like what I was asking of them. Now I’m a smidge worried. If they added my email address to their spam filter, does that mean I’m somehow going to be pegged as a spammer in the larger Internet world? I seem to recall that someone once told me that anytime someone clicks that a message is spam, it’s a strike against you. Enough strikes and we’re in trouble. I don’t remember how many strikes he said it took to be in trouble, though.

So…am I worrying about nothing? Or should I do something about it, if there’s anything to do, that is?

The answer is simple: do nothing.

The reason behind the answer, naturally, is quite complex.

Spam filters – particularly good spam filters – rely heavily on users marking things as spam. In a way, it’s a form of “crowd sourcing”, where  the actions of users build a database used to determine what is and is not spam in subsequently received emails.

Where your email is marked as spam, and who is doing the marking, has a lot to do with any potential impact on emails you send in the future.

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Where it’s marked as spam

There are two places that someone might mark an email as spam:

  • In an email program, like Microsoft Office Outlook, Thunderbird, Windows Live Mail, Outlook Express and so on.
  • In an online email service, like Gmail, Yahoo! Mail, and others.1

We can pretty much rule out the first one as a problem for you right away.

Marked as spam on the desktop

When someone marks a message as spam in a desktop email program, that information typically applies only to the individual doing the marking, and only on that specific email program, installed on that specific computer.

In other words, marking as spam in an email program doesn’t actually impact anyone else at all.

Mark As SpamYes, if your email gets marked as spam enough times, email from you may go directly to that person’s spam folder, but only for that person.

That scenario is nothing you have control over, but also nothing you need to worry about.

Online is a slightly different story – but only slightly.

Marked as spam online

I’ll use Gmail as an example, using its Web interface, but the concepts generally apply to most online email services that provide some kind of spam filtering.

When someone marks your message as spam, Gmail may take that as a mark against you that could impact your deliverability to others also on Gmail. But only for other recipients on Gmail.

The bottom line here is that for shared online services, that “mark against you” applies only to that specific shared online service. Get enough marks as spam from Gmail users, and the Gmail spam filter will start dropping your messages into the spam folder.

Or will it?

Practical effects of being marked as spam

The problem is that spam filters are incredibly complex. They look at much more than who sent the email. Remember, in “real” spam, the “From:” line can be completely spoofed, which makes it an unreliable indicator of spam all by itself.

Instead, email service spam filters look at:

  • The content of the messages.
  • The reputation of the email service or server being used to send the mail.
  • Timing.
  • The number of recipients.
  • And much more.

In fact, just about any email characteristic you can think of – and probably several you can’t – are factors in determining what is and is not spam. So it may mean nothing at all if one person keeps marking you as spam, even on a shared system.

Personalized results

If someone marks your email as spam often enough, your email may end up being considered spam for them.

Even on a shared system like Gmail, spam filters can be different for each recipient. What Gmail considers spam for you might be different than what it considers as spam for me, because we consistently mark different kinds of things as spam.

That means if one person marks your messages as spam a bunch of times, and others do not, Gmail might say, in effect, “well, this person thinks it’s spam, so I’ll just spam it for him alone”. As soon as you start getting multiple reports from multiple different recipients, a more global algorithm is likely to kick in.

And yet…

Here’s where things get even more vague.

I use Gmail as my example because it has one of the best spam filters out there. Other services have spam filters of various levels of quality and capability … or close to none at all. So everything I just described for Gmail might not happen for, say, Microsoft (,,,, etc ), or happen to different degrees or with different rules.

If someone has email based on their own web hosting (folks who have custom domains, and email addresses on those domains), their spam filter may do something else entirely.

It’s incredibly difficult to know.

The “larger internet world” doesn’t really exist

In reality, when it comes to spam filtering, there’s really no “larger internet world”, at least at the level of the individual sender.

When one person marks your message as spam it may:

  • Make it more likely your email to that person will end up in their spam folder.
  • Might make it very slightly more likely that your email to others using the same email service might end up in their spam folders.
  • Not affect your ability to deliver to anyone else.

I guess that’s a really long answer that, for the scenario you describe, boils down to: don’t worry about it.

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Footnotes & references

1: Most mobile apps are, in a sense, extensions of the online service, when they are specifically written for that service. General purpose mobile email programs operate like the desktop equivalents, if they even have a “mark as spam” feature at all.

15 comments on “Should I Worry If Email I Send Is Marked as Spam?”

  1. OK ,, I know a few webpages that will not let me on unless I ask an ADMIN to clear it up (they usually don’t know what I am talking about, at first) until their techy person can clear it up ,, then ,, there are a few websites (products or services I am inquiring about) I have responded to through their webpage messaging and NO Response ( extremely annoying) I think I am marked as Spam ,, Then again ,, While searching for something, I encountered a website that gave a message that said “My computer is prohibited from accessing the page as it was marked as spam 3 times” (something like that)

    How to know and correct this situation ??

    • Computers are not marked as spam, so I’m afraid I don’t understand your question. Email messages are marked as spam. And getting anything marked as spam should not prevent you from accessing any web sites – it just means your email may land in someone’s spam folder, that’s all.

  2. Some interesting points on spam.
    We must realise that most of what is called spam is bad marketing and lousy manners.
    It is not long term business building.
    To understand what to do and what not to do you must study “real marketing and Psychology”.
    It is not a computer or IT problem, its a human problem.

  3. What the person got was a lesson about dealing with a cranky employee, and another lesson that if they have a problem to resolve, email is not always the way to do it.

    Also that they should learn to NEGOTIATE over business problems instead of demanding, seek MEDIATION.

    They may have just found that they should just go somewhere else and accept that it isn’t going to work like they want.

    NONE of this is a computer problem, it’s a HUMAN RELATIONS or CIVIL MATTER. Perhaps the local Chamber Of Commerce or Better Business Bureau, a lawyer or state’s attorney general’s office.

    But it’s not a computer problem at all, it’s a communication issue in general.

    • It is one of many, many different services that try to provide information about spammers. With spammers constantly changing email addresses, using others email addresses, hacking machines and changing servers, there’s nothing really to put into a “database of spammers” that would work.

  4. Hi Leo,

    What about this paragraph from the MX Toolbox website? This is what I have always been concerned about when people mark any of our business emails as spam:
    The blacklist test will check a mail server IP address against over 100 DNS based email blacklists. (Commonly called Realtime blacklist, DNSBL or RBL). If your mail server has been blacklisted, some email you send may not be delivered. Email blacklists are a common way of reducing spam. If you don’t know your mail server’s address, start with a MX Lookup. Or, just send an email to

    Thanks for your feedback! Love your newsletter :)


    • Yep. Email servers (not your IP, but the email service you use) that send a lot of spam can be black listed. The blacklists are inaccurate, and not universally used, but they do exist. But, again, they don’t apply to individuals, but rather to the servers that send mail on your (and a lot of other people’s) behalf.

  5. Sir,
    Really a nice article on spam. A small doubt, of course . There are spam filters which mark so many IPS nos country wise . I also wonder, that most of the service providers are having dynamic IPS. Would not one , at no fault of his, would log in the IP of filtered spam by those organisation, as marked as spam when he tries to visit genuine website, which has enabled spam filters for their site.
    What is the solution for this? Sir,

  6. Hey Leo,

    Awesome article, very helpful! I know I’m pinging a post a year old now but I had 2 questions I hope you can shed some light on:

    1) I use gmail to send and receive business emails but it is all filtered through a company email address. If I was marked as spam, which would be affected: gmail or company?

    2) I use a template introductory email (kind of) but for its 100+/- words it has at least 20 variable to make the email personal and is only ever sent to one person. When you say the “content of the email” is evaluated for potential spam, would these similar emails typically be regarded as the SAME “spammy” message sent hundreds of times individually to different people? I ask because I’ve seen the phrase “others have marked messages like this spam” in my spam folder.

    Thanks for your time and help, Leo!

    • 1) Marking as spam in gmail only adds to gmail’s spam filter.

      2) All I can say is “maybe”. It’s MUCH more complex than a simple yes or no could offer. If people mark your emails as spam, and you send a lot of emails that look similar then it’s possible your others could be flagged as spam as well.

  7. Is there another way to block emails from a source that is perfectly legitimate, not SPAM at all, but I just don’t want to get any more messages from them? Since I’m using Gmail, it appears I will, however mildly, injure them somewhat if I mark their messages as SPAM and I don’t want to do that. Most of these are offers of some sort. Thanks much Leo.

    • If it’s legitimate then you should be able to unsubscribe. If there’s no option to do so, then it is spam and you should mark it as such.

      The only other solution I’m aware of is to set up a filter in Gmail to auto-delete the messages meeting your criteria on arrival.

  8. Great article thanks. My question is like an inversion – Gmail sends too much into my spam folder. “All mail” still doesn’t show mail in the spam folder. I’m fed up marking mail from friends as NOT SPAM when I’ve discovered them in spam. Again. What’s the best way of dealing with this?

    • Doing what you’re doing — marking them as “not spam”.

      The only other solution I’m aware of is if you have a consistent sender that’s always getting sent to spam, you can set up a filter in Gmail and tell it “never mark as spam”.


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