Summary
Even with a rigorous double opt-in process, email marketers can still encounter spam traps primarily due to recycled addresses. These traps originate from legitimate email addresses that were once opted-in and active but have since been abandoned and repurposed by Internet Service Providers (ISPs) to identify senders of unsolicited mail. Spam traps are universally passive and do not open, click, or interact with emails in any way. Any perceived engagement from these addresses is typically a result of automated systems, not the traps themselves. While a few isolated hits, especially within systems like Microsoft SNDS, might not be alarming, their presence underscores the ongoing need for robust list hygiene to maintain deliverability.
Key findings
- Recycled Spam Traps: The primary reason for hitting spam traps with double opt-in (DOI) confirmed addresses is due to recycled spam traps. These are legitimate email addresses that were once human-used and opted-in, but became dormant, were abandoned, and subsequently repurposed by Internet Service Providers (ISPs) into traps to catch senders of unsolicited mail, as explained by Mailgun Blog, Spamhaus, SendGrid, Twilio SendGrid, Laura Atkins, Simon Davies, Postmark, and Aweber.
- Spam Traps Are Passive: Spam traps are designed to be entirely passive entities that do not physically click, open, engage with emails, or reply. Any recorded activity like clicks or opens associated with a spamtrap is typically attributed to automated processes, such as proxies, security software, or pre-fetching services, rather than direct interaction by the trap itself. This consensus is shared by Mailgun Blog, Spamhaus, u/deliverability-guy, SendGrid, Twilio SendGrid, Laura Atkins, Simon Davies, Validity, Postmark, Aweber, and Spam Resource.
- Microsoft's Behavior: While most spam traps are inactive, Microsoft's SNDS (Smart Network Data Services) might occasionally follow links, which could give the perception of 'clicking' spam traps. However, Microsoft states they no longer recycle addresses as traps, and one or two spamtrap hits in their system are common and generally not a concern, according to an Email Geeks expert.
- Dormancy Period: ISPs convert old, inactive email addresses into traps, often after a significant period of dormancy, ensuring these are truly abandoned accounts before repurposing them.
Key considerations
- List Hygiene: Even with double opt-in, regular list cleaning is essential to remove inactive email addresses before they are repurposed as recycled spam traps by ISPs, as emphasized by Validity and Aweber.
- Recycled Address Seasoning: Competent spamtrap networks allow recycled addresses to bounce mail for at least 12 months before converting them into traps, as noted by an Email Geeks marketer.
- Broader Deliverability Issues: While spam traps are a specific problem, hitting them can also indicate broader delivery challenges, not always the sole or primary issue, a point highlighted by an Email Geeks marketer.
- Other Trap Types: Beyond recycled addresses, double opt-in lists might encounter typo traps from sign-up errors or malicious sign-ups where bad actors intentionally add trap addresses, according to an expert from Word to the Wise.
What email marketers say
7 marketer opinions
Despite implementing double opt-in for email list acquisition, senders frequently encounter spam traps. This phenomenon is predominantly explained by the repurposing of old, legitimate email addresses by Internet Service Providers after these addresses have become inactive. These recycled addresses, once part of an active subscriber base, are then used to identify mailers who do not adequately manage their lists. Crucially, spam traps are passive entities by design and do not perform any engagement actions such as clicking links, opening emails, or replying.
Key opinions
- Recycled Address Origin: Even with double opt-in protocols, the presence of spam traps often points to recycled addresses. These traps stem from email addresses that were once valid, active, and legitimately subscribed but have since been abandoned and subsequently repurposed by Internet Service Providers (ISPs).
- Spam Trap Passivity: Spam traps function purely as detection mechanisms and exhibit no active engagement. They do not click on links, open emails, or send replies, acting as inert indicators of list quality.
- Seasoning Period: A notable characteristic of recycled spam traps is their 'seasoning' period. Before an abandoned, inactive email address is converted into a trap, spamtrap networks typically let it remain dormant for an extended duration, sometimes exceeding 12 months, during which time emails to it would result in bounces.
Key considerations
- Ongoing List Hygiene: Maintaining rigorous list hygiene remains paramount, even for double opt-in lists. Proactively removing inactive or very old subscribers is crucial to reduce the likelihood of encountering recycled spam traps.
- Broader Deliverability Indicator: Spam trap hits, while problematic on their own, often signal more extensive deliverability issues. They can act as an alert to investigate broader sending practices and list quality, rather than being the sole focus of concern.
Marketer view
Marketer from Email Geeks explains that hitting spamtraps with DOI confirmed addresses can be due to recycled addresses that were once human-used, noting that competent spamtrap networks season these addresses by bouncing mail for at least 12 months. He also clarifies that spamtraps are often a simplified explanation for broader delivery issues, not always the sole or primary problem.
25 Feb 2024 - Email Geeks
Marketer view
Email marketer from Mailgun Blog explains that even with double opt-in, senders can hit recycled spam traps, which are old, inactive email addresses that Internet Service Providers (ISPs) convert into traps. These traps are passive and do not click, open, or engage with emails in any way.
11 Feb 2023 - Mailgun Blog
What the experts say
3 expert opinions
Double opt-in processes significantly enhance list quality, yet they do not completely eliminate the risk of encountering spam traps. This can occur when previously valid addresses are recycled by Internet Service Providers, through the addition of typo traps from user sign-up errors, or even malicious injections of trap addresses. It's crucial to understand that spam traps themselves are passive and do not engage with emails; any reported clicks or opens are typically due to automated security systems or pre-fetching services, with Microsoft's SNDS being a notable exception that may occasionally follow links.
Key opinions
- Spam Trap Origins: Even with double opt-in processes, lists can encounter spam traps due to recycled addresses (former valid emails repurposed by ISPs), typo traps (sign-up errors), or malicious sign-ups (intentional additions of trap addresses by bad actors).
- Trap Interaction: Spam traps are inanimate entities; they do not physically open, click, or unsubscribe from emails. Any recorded activity associated with a spamtrap, such as opens or clicks, is typically the result of automated processes, including proxies, security software, or pre-fetching services.
- Microsoft's Nuance: While most spam traps are passive, Microsoft's SNDS may occasionally follow links, which can create the perception of 'clicking' spam traps. However, Microsoft states they no longer recycle addresses as traps.
Key considerations
- Beyond Recycled Addresses: While recycled addresses are a primary concern, be aware that spam traps can also originate from typo errors during sign-up or from malicious actors intentionally adding traps to your list.
- Microsoft SNDS Hits: A few isolated spam trap hits within Microsoft's system are generally common and often not a cause for alarm, even if their system appears to 'click' links occasionally.
- Ongoing List Management: Even with double opt-in, maintaining a clean list by regularly removing very old or inactive addresses is crucial to minimize exposure to recycled spam traps.
Expert view
Expert from Email Geeks explains that Microsoft's SNDS might occasionally follow links, which could contribute to the perception of 'clicking' spamtraps, and suggests that very old addresses could also be a factor. She adds that while Microsoft states they no longer recycle addresses as traps, one or two spamtrap hits in Microsoft's system are common and generally not a cause for concern.
15 Aug 2022 - Email Geeks
Expert view
Expert from Word to the Wise explains that even double opt-in lists can contain spam traps due to recycled addresses, which were once valid but abandoned and repurposed, typo traps resulting from sign-up errors, or malicious sign-ups where bad actors intentionally add trap addresses to a list.
10 Nov 2024 - Word to the Wise
What the documentation says
4 technical articles
Even with double opt-in, email marketers may encounter spam traps because legitimate, opted-in addresses can become dormant and subsequently repurposed by Internet Service Providers into recycled traps. It's crucial to understand that these spam traps are designed to be entirely inactive; they do not open emails, click on links, or engage in any form of interaction. This phenomenon underscores the ongoing necessity for meticulous list hygiene, even for lists acquired through robust double opt-in methods.
Key findings
- Recycled Addresses: Senders can hit spam traps with double opt-in email addresses primarily because legitimate, once-active addresses are abandoned and subsequently repurposed by Internet Service Providers (ISPs) into recycled spam traps.
- Trap Inactivity: Spam traps are passive entities designed not to interact with emails. They do not open, click links, or engage in any other actions, serving solely as indicators of unsolicited mail or poor list management.
- ISP Repurposing: ISPs recycle dormant email addresses to catch senders of unsolicited mail, meaning an address that was initially double opted-in can eventually become a trap if it goes inactive for a prolonged period.
Key considerations
- Ongoing List Hygiene: Even with a double opt-in process, consistent list hygiene is vital. Regularly cleaning your list by removing inactive or unengaged addresses helps prevent them from being converted into recycled spam traps by Internet Service Providers.
- Beyond Opt-in: While double opt-in establishes initial consent, it does not guarantee lifelong validity of an email address. Addresses can become traps over time due to abandonment, necessitating ongoing attention to list health.
Technical article
Documentation from Spamhaus Resource Center clarifies that recycled spam traps are legitimate, abandoned email addresses repurposed by ISPs to catch senders of unsolicited mail. This process can affect addresses that were initially double opt-in but became dormant. Spam traps are designed to be inactive and do not open, click, or engage with emails.
16 Jan 2024 - Spamhaus Resource Center
Technical article
Documentation from Twilio SendGrid's Delivery Guide explains that while double opt-in is a strong starting point for list building, email addresses that were once valid can become recycled spam traps if they are abandoned and later repurposed by ISPs. Consequently, senders might hit these traps even with a double opt-in list. It also states that spam traps are inactive and do not perform actions like clicking or opening emails.
7 Jun 2022 - Twilio SendGrid Delivery Guide
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