How spam words are triggering the spam filter

Over the past few years, we’ve seen ISPs become a bit smarter and have started to move away from more traditional spam alarms. Today, ISPs learn from how we interact with the messages that arrive in our inbox, which helps them determine whether emails should go to the Spam folder or land safely the inbox.


So what does this means for words you should (and should not) be including in subject lines, then? Well, words tend to be misleading, thus resulting in higher-than-normal user complaint rates. These complaints, along with poor interaction from recipients have a negative effect on the sender reputation and, ultimately, impacts the delivery of future messages.


Just imagine how many times you have received a subject line that includes the word “Free”. How many times has there actually been something that’s truly free in the email? Probably very few, which explains why now, when you read the word “Free” in your inbox, you generally just roll your eyes at a not-so-subtle attempt to get you to open a deceiving email. If people do open the email and then find that there’s actually nothing really free there, senders can expect a high rate of user complaints like spam reports and unsubscribes that will impact their future inbox placement.


Avoid these words they trigger spam filters

  • Invoice - The word “invoice” is a phisher’s favorite – if you see this word in a subject line, there’s a chance they’re trying to bait you in. Make sure to check the sender address to verify the email’s validity. billing@ex-ample.com is not the same as billing@example.com. Scammers try to profit out of our carelessness.
  • Any Bank Name, PayPal, Visa/MasterCard, etc.  - Scammers often try to impersonate financial institutions by sending emails with the same color scheme and layout, redirecting to a mirrored site made to look almost exactly like the one it is spoofing.
  • Free, Lottery, Gift or Prize - This is one you always see in your spam folder. Hundreds of thousands of emails are sent to people with a subject line claiming that they’ve just won a big prize or that they’ve been selected for a sweepstakes you’ve never entered before. You have to be very gullible to fall for that one, yet scammers still send these by the millions since they are quick and easy to send. If it’s too good to be true, then it is.
  • Help, Urgent, Desperate, Plea - Variations of this “damsel in distress” scheme have made appearances over the years, where phishers pretend to be an affluent person from a far away country, who, being chased by wrongdoers, is forced to flee to a safe haven. For some reason they have chosen you as the sole trustee of all their money and they promise great rewards for helping them open an account with a specific bank so that they can transfer their funds.
  • Free Prize, Free Spin, Casino, Deposit Bonus - Gambling spammers often send out campaigns that promise high return, free entry or double deposits. If it’s not a website you recognize, then straight to the spam folder it goes.


Additional words to avoid using


Spam Words