Summary
Sending emails to outdated or poorly maintained lists results in high bounce rates, which signals poor list hygiene to ISPs and mailbox providers. This negatively impacts sender reputation, increases the likelihood of emails being marked as spam, and may trigger spam filters or ESP investigations. Experts recommend implementing regular list cleaning, using email validation tools, and avoiding sending to stale data to maintain email deliverability. High bounce rates can also lead to account limitations with email service providers like Amazon SES.
Key findings
- High Bounce Rate = Spam: High bounce rates directly contribute to emails being classified as spam by ISPs and mailbox providers.
- Old Lists = Poor List Hygiene: Sending to old, unmanaged lists results in poor list hygiene, damaging sender reputation and impacting deliverability.
- ISPs Use Bounce Rates as Metric: ISPs use bounce rates as a key metric to assess sender trustworthiness and the quality of their email practices.
- Validation tools are useful: Email validation tools can identify and remove invalid email addresses prior to sending.
- Account Limitations: High bounce rates can lead to account limitations with ESPs like Amazon SES.
Key considerations
- Regular List Cleaning: Implement a process for regularly cleaning and updating email lists to remove invalid or inactive addresses.
- Use Email Validation Tools: Employ email validation tools to identify and remove invalid addresses before sending.
- Monitor and Manage Bounce Rates: Actively monitor bounce rates and take steps to keep them within acceptable limits.
- Avoid Stale Data: Avoid sending emails to old or unengaged addresses to minimize bounce rates.
- Maintain opt-in practices: Ensuring opt-in practices are up to date to ensure subscribers still want to receive email.
What email marketers say
9 marketer opinions
Sending emails to old or unmaintained lists results in high bounce rates, signaling poor list hygiene to Internet Service Providers (ISPs). This damages sender reputation, increases the likelihood of emails being marked as spam, and may lead to hitting spam traps. Maintaining a clean and up-to-date email list is critical for ensuring email deliverability.
Key opinions
- High Bounce Rate = Poor Reputation: High bounce rates are a key indicator of poor list hygiene, damaging your sender reputation with ISPs.
- Old Lists = Deliverability Issues: Sending to old, unmaintained lists leads to deliverability problems and increases the chances of emails landing in the spam folder.
- ISPs Use Bounce Rates: ISPs use bounce rates as a metric to assess sender trustworthiness and the quality of their email practices.
- Spam Traps: Old lists are likely to contain spam traps, further harming sender reputation when triggered.
Key considerations
- Regular List Cleaning: Implement a process for regularly cleaning and updating email lists to remove invalid or inactive addresses.
- List Hygiene: Practice good list hygiene to maintain a positive sender reputation and ensure better deliverability.
- Bounce Rate Monitoring: Monitor bounce rates closely to identify and address issues promptly to prevent deliverability problems.
Marketer view
Email marketer from Email on Acid mentions that bounce rates are an important metric used by ISPs. A high bounce rate is a sign of poor list hygiene, which can get your emails sent straight to the spam folder.
2 Nov 2024 - Email on Acid
Marketer view
Email marketer from SendGrid explains that when lists aren't cleaned then sending to old data causes high bounce rates which will directly effect your reputation, resulting in emails going straight to spam.
30 Aug 2024 - SendGrid
What the experts say
9 expert opinions
Sending emails to old or poorly maintained lists results in high bounce rates, which significantly damages sender reputation. ISPs interpret this as a sign of poor list hygiene, leading to emails being flagged as spam. A high bounce rate can also trigger spam filters and may even lead ESPs to investigate the source and permission status of the email addresses. Utilizing email validation tools and avoiding sending to stale data are crucial for maintaining email deliverability.
Key opinions
- High Bounce Rate = Spam Risk: Bounce rates significantly above 1% are a strong indicator of list quality issues and drastically increase the likelihood of emails landing in spam folders.
- Old Lists = Poor Quality: Old, unmanaged lists contain invalid addresses, spam traps, and unengaged recipients, negatively impacting deliverability.
- Sender Reputation Damage: High bounce rates directly damage sender reputation, leading ISPs to view senders as less trustworthy.
- ESP Scrutiny: Extremely high bounce rates may trigger investigations by email service providers regarding the legitimacy and consent practices of the sender.
Key considerations
- List Validation: Implement email validation tools and processes to remove invalid and risky email addresses before sending.
- Avoid Stale Data: Refrain from sending emails to old or unengaged email addresses; prioritize list cleaning and opt-in practices.
- Diplomatic Communication: When addressing concerns about deliverability issues stemming from old lists, communicate the risks and best practices clearly and professionally, emphasizing the potential consequences for overall email deliverability.
- Bounce Rate Monitoring: Monitor bounce rates to ensure they are kept below acceptable limits, ideally below 1%.
Expert view
Expert from Email Geeks attributes the email delivery issues (going to spam) to an old and potentially not opt-in mailing list. She states the filtering is reflecting the poor quality of the list.
3 Aug 2022 - Email Geeks
Expert view
Expert from Email Geeks advises against further sending to the problematic list, emphasizing that it will further damage the mailstream reputation. She suggests including language about potential ESP investigations and internal compliance standards.
31 Jan 2022 - Email Geeks
What the documentation says
4 technical articles
High bounce rates resulting from sending to invalid, inactive, old, or unverified email addresses negatively impact sender reputation, leading major email providers like Google, Microsoft, SparkPost, and Amazon SES to classify emails as spam or junk. Exceeding acceptable bounce rate thresholds can result in account limitations to protect their overall user experience.
Key findings
- High Bounce Rate = Spam: Major email providers use high bounce rates as a key signal to identify and filter spam.
- Old Lists = Bounce Risk: Sending to old or unverified lists significantly increases the risk of high bounce rates.
- Reputation Impact: High bounce rates damage sender reputation, impacting the deliverability of future emails.
- Account Limitations: Exceeding acceptable bounce rate limits (e.g., 5% with Amazon SES) can result in account limitations.
Key considerations
- List Verification: Regularly verify email lists to remove invalid or inactive addresses.
- Engagement Monitoring: Monitor engagement metrics to identify and remove unengaged subscribers.
- Bounce Rate Management: Actively manage bounce rates and ensure they remain within acceptable limits to maintain good sender reputation.
Technical article
Documentation from Google Postmaster Tools explains that sending emails to invalid or inactive email addresses contributes to high bounce rates. These high bounce rates are a signal that can cause Google to filter your emails as spam.
3 Dec 2022 - Google Postmaster Tools
Technical article
Documentation from SparkPost details that high bounce rates from old or unverified lists significantly harm sender reputation, leading ISPs and mailbox providers to classify your emails as spam to protect their users.
9 Jan 2025 - SparkPost
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