Definition of Spam Trap.

To put it simply, a "spam trap" (or commonly known as a "trap") is an address that accepts mail but does not belong to a real user. There are two main types of traps: pristine and recycled.

Pristine spam traps are addresses that never belonged to a real user, and never signed up for any mail. Mailing to (or "hitting") this type of trap address is very serious because it means that the address was "scraped" from the Internet. You generally end up with these addresses on your list as a marketer if you have purchased a list of addresses or a naughty affiliate of yours engages in purchasing lists or scraping addresses. Any way you slice it, it's very bad to mail to those addresses and is indicative of poor acquisition practices.

Recycled spam traps are previously active addresses, which potentially belonged to a real user, but have been repurposed as a trap address after 6 or more months of inactivity and "conditioning" (meaning they returned a hard bounce error for a reasonable amount of time). It's easy to end up with this type of trap address on your mailing list as a marketer if you don't practice good list hygiene by removing inactive and invalid accounts regularly.

The bottom line is: These addresses have no value to you as a sender since no one is on the other end reading your email. No good will come from mailing to spam traps.