Spamtraps strike fear into the heart of senders. They’ve turned into this monster metric that can make or break a marketing program. They’ve become a measure and a goal and I think some senders put way too much emphasis on spamtraps instead of worrying about their overall data accuracy.
Recently I got a question from a client about the chances that any address they were currently mailing would turn into a recycled spamtrap. Assuming both a well behaved outbound mail server and a well behaved spamtrap maintainer the answer is never. Well behaved spamtrap maintainers will reject every email sent to one of their spamtrap feeds for 6 – 12 months. Some reject for longer. Well behaved mail servers will remove addresses that consistently bounce and never deliver.
Of course, not everyone is well behaved. There are maintainers who don’t actively reject mail, they simply pull the domain out of DNS for years and then start accepting mail. Well behaved mail servers can cope with this, they create a fake bounce when the get NXDomain for an address and eventually remove the address from future mailings. There have been cases in the past where spamtrap maintainers purchase expired domains and turn them into spamtraps immediately. No amount of good behaviour on the part of the sender will cope with this situation.
On the flip side some MTAs never correctly handle any undeliverable address when the reason is anything other than a direct SMTP response. Generally these are built on the open source MTAs by people who don’t realise there are mail failures outside of SMTP failures.
There are three general cases where recycled spamtraps will show up on a list.
- A list has been improperly bounce handled.
- An address has not been mailed for more than a year.
- Someone signs up an address that’s a recycled spamtrap (same as how a pristine trap will get added to a list)
ESPs have to worry about recycled spamtraps in another common case. A new customer brings over a list and decides to retry addresses that their previous ESP marked as bounced. (It happens. Regularly.)
Recycled addresses are a sign that there is a problem with the long term hygiene of a list. As with any spamtrap, they’re a sign of problems with data collection and maintenance. The traps aren’t the problem, they’re just a symptom. Fix the underlying issue with data maintenance and traps cease to be an actual issue.