Spam traps are a tool used by Internet Service Providers (ISP’s) to identify and track spammers. Essentially, they are an unmonitored email address that alerts an ISP anytime an email lands in its inbox. If by some chance you send an email to this address, you will get flagged as a spammer and you will find it extremely difficult to get any of your email delivered.
There are two types of spam traps you should be aware of: Pure spam traps (Pristine Spam Traps), and Recycled spam traps. Pristine traps are email addresses that are published on public websites but are hidden so you never see them. The only people who find and send to those addresses are the people who use bad collection processes, like scouring the web for anything that looks like an email address. If you obtained addresses by scraping them from web pages—or bought a list, which often include scraped email addresses—you may have picked up a pristine spam trap.
Recycled spam traps, on the other hand, could have been active email addresses at one point in time. That means they might have just gone dormant or inactive, and they've been taken over by the ISP after a period of inactivity.
If you send an email to this address, ISPs will deliver a hard bounce notification to you, so you are aware that you are emailing an inactive account. It's at that point that you should remove the email address from your list. After a few months, ISP’s convert those email addresses into recycled spam traps and stop delivering hard bounce notifications to email senders. If you keep emailing that address, they'll mark it as a spam trap hit.
How to avoid spam traps
It’s simple, spam traps are there for a very good reason. Everyone hates spam. If you don’t want to be caught in a spam trap, here are a few tips:
Don’t purchase email lists! They are rife with spam trap email addresses.
Don’t harvest lists from the internet or on websites unless you are sure they are active. They can be spam traps!
Remove hard bounces from your email lists.
Where possible, use a double opt-in or validate new email addresses. By doing this, you can ensure that an email address belongs to a real person.
Manage your inactive subscribers. Inactive subscribers are not of much value to your campaigns and some of these addresses are at risk of being converted into dead address spam traps.
By doing the above, you can actively avoid getting any spam traps into your database and you don’t get flagged as a potential spammer. Which will ensure that your mail gets delivered to the intended recipient. These are the only certain ways to prevent your organisation from hitting spam traps. If you already have spam traps on your list, you're in a dire situation; but there is recourse. Time consuming recourse. You will need to reconfirm everyone on your email list. Be warned, that will drastically decrease the size of your database.
General tips to avoid being flagged as a spammer
Use Fewer Exclamation Points
We get that you have a great offer but using an excessive amount of exclamation points in your copy (and your subject field) can get you caught in a spam filter. Try to limit yourself to one or two uses of an exclamation point, per email.
Avoid using all caps
If you want to get caught in a spam filter USE CAPS EXCESSIVELY IN YOUR EMAIL COPY. It is perfectly fine to use CAPS when necessary, just don't write the whole email like that or you'll get flagged.
Don't send your emails as a single image
Spam filters can’t see images. So, if your entire email is just one large picture with your copy on it, the chances are high that the spam filter will catch you. The filter can see that the email has content, can see the size of the email itself but if it can’t see text, it’ll think you are trying to trick it and send your mail packing.
Avoid phrases like “Buy Now”
Certain phrases are commonly identified by spam filters as “spammy” because they have been used in the past by spammers. Such phrases include “click here” and “buy now”. Instead, keep your subject lines and call-to-actions focused on what’s in it for the reader.
Ensure you practice good marketing techniques, get your email addresses the right way, sanitise your email database on a regular basis and try to use a double opt-in/email verification approach. That will ensure that the people who sign up to your email database are real and will keep you from being caught in a spam trap and registered as a spammer.