What is the main risk of sending emails to inactive contacts?

The primary risk is damage to your sender reputation, which is a score mailbox providers assign based on your sending habits. Sending to inactive users often results in low open rates, high bounce rates, and increased spam complaints, signaling to ISPs that your emails are not valuable. This can lead to your emails being filtered to spam folders or blocked entirely, even for your active subscribers.

Is it bad to define inactive contacts too aggressively, like after only one month?

An aggressive definition (e.g., classifying someone as inactive after only 1 month) can be detrimental. Many legitimate subscribers may not open every email but still value your content. Too quick a removal can lead to lost engagement, and from an ISP perspective, it might even look like spammer behavior if you're rapidly discarding non-responsive addresses. A more balanced approach, like 3-6 months, is generally recommended.

Can sending to inactive contacts lead to hitting spam traps?

Yes, spam traps are email addresses used by ISPs and blocklist operators to catch senders with poor list hygiene. If you send to an inactive address that has been converted into a spam trap, your domain or IP can be immediately blacklisted (or blocklisted). This is a serious risk and a key reason to regularly clean your email list.

What's the best strategy to re-engage inactive contacts without harming deliverability?

Re-engaging inactive contacts should be done cautiously. Start by segmenting them and sending very small batches alongside your highly engaged lists. Monitor engagement closely. If a contact responds, you can gradually increase their sending frequency. If they remain unresponsive after a few attempts, it's often best to remove them from your active mailing list to protect your sender reputation.

How does sending email to inactive contacts affect deliverability? - Sender reputation - Email deliverability - Knowledge base

Sending emails to inactive contacts is a common practice for many marketers looking to re-engage their audience or simply broaden their reach. However, this approach carries significant risks for your email deliverability. While it might seem like a simple way to increase your contactable base, the potential negative consequences can far outweigh the benefits, impacting your ability to reach even your most engaged subscribers.

The core issue lies in how mailbox providers assess your sender reputation. They closely monitor how recipients interact with your emails. When you send to addresses that consistently show no engagement, such as opens or clicks, it signals to these providers that your emails might not be valuable or, worse, unwanted. This behavior can quickly degrade your sender reputation, making it harder for all your emails, even those to active users, to land in the inbox.

A crucial distinction exists between truly inactive users and those who simply don't open every email. Some users might read your content directly from their inbox preview, or visit your website directly without clicking a link in an email. Defining inactivity too aggressively can lead to prematurely pruning valuable contacts from your list. On the other hand, neglecting to manage genuinely inactive contacts can lead to a host of deliverability problems, from increased bounce rates to being marked as spam.

The impact on sender reputation

One of the most immediate and significant impacts of emailing inactive contacts is the damage to your sender reputation. Mailbox providers, such as Gmail and Outlook, track engagement metrics like open rates, click-through rates, and spam complaints. A low engagement rate from a large segment of your list indicates to these providers that your content may not be relevant or desired. This can lead to your emails being flagged as spam or even blocked entirely for all recipients, not just the inactive ones. Poor sender reputation is a major barrier to successful deliverability.

Another serious risk is encountering spam traps. These are email addresses set up by mailbox providers and blocklist operators to identify senders who are not maintaining clean lists. Sending to a spam trap can instantly get your IP address or domain blacklisted (or blocklisted). This can severely hinder your ability to reach any inbox, as many providers use these blocklists to filter out unwanted mail. Even a single hit on a high-value spam trap can have devastating consequences for your email program.

Beyond spam traps, regularly emailing inactive addresses increases your hard bounce rate. Hard bounces occur when an email address no longer exists or is permanently disabled. High hard bounce rates signal to mailbox providers that you have a low-quality list, which negatively impacts your sender reputation. Mailbox providers see this as irresponsible sending, and it can lead to your legitimate emails being sent to the spam folder or rejected outright. The risks of sending to inactive users are varied, but all point to a decrease in deliverability.

Risks of emailing inactive contacts

Lower engagement metrics: Significantly lower open and click rates, signaling to ISPs that your emails are not relevant to recipients.
Increased spam complaints: Inactive users are more likely to mark your emails as spam, which is a severe blow to your reputation.
Higher bounce rates: More emails bouncing due to dead or disabled addresses, increasing the risk of blocklisting.
Spam trap hits: Risk of hitting addresses repurposed as spam traps, leading to immediate blocklists.

Identifying inactive contacts

Defining an inactive contact is the first crucial step in managing your email list effectively. While a common threshold is often set at three to six months of no engagement, this can vary significantly based on your industry, email frequency, and customer lifecycle. Some businesses might consider a contact inactive after just a month, while others might extend that to a year or more. The key is to establish a definition that aligns with your specific sending patterns and audience behavior.

Once you have a definition, segmenting your list allows you to treat active and inactive subscribers differently. This means separating contacts who consistently open and click from those who don't. Segmentation is essential because it prevents you from applying the same sending strategy to vastly different segments of your audience. Sending targeted campaigns to engaged users helps maintain a strong sender reputation, while a separate approach can be designed for inactive contacts.

For contacts inactive for a shorter period, a targeted re-engagement campaign can be effective. This involves sending a series of emails designed to pique their interest, perhaps offering exclusive content, a special discount, or simply asking if they still wish to receive your emails. However, for contacts that have been inactive for six months or longer, the risk of hitting spam traps or generating complaints increases significantly. For these, a more cautious approach, or even removal, is often advisable to protect your overall deliverability.

Inactivity definition

Inactivity is typically defined by a lack of engagement (opens, clicks, replies) over a specified period. This period should be carefully chosen to reflect realistic user behavior and your sending frequency. An overly aggressive definition, such as one month, might incorrectly categorize valuable subscribers as inactive. On the other hand, a definition that is too lenient, like over a year, significantly increases the risk of mailing dead addresses and spam traps.

Strategic re-engagement and list cleaning

When attempting to re-engage inactive subscribers, the volume of emails you send is critical. A sudden, large campaign to a segment of highly inactive contacts can result in a significant spike in negative metrics, such as low engagement rates and high spam complaints. This can quickly damage your sender reputation and trigger filters for all your future mailings. It is far safer to gradually introduce these contacts back into your sending stream, mixing a very small number of inactive addresses with your regularly engaged list.

For instance, if you usually send 100,000 emails a day to engaged subscribers, adding 100-500 inactive contacts to that mailing (0.1% to 0.5% of your total send) would be a cautious approach. This small volume allows you to test the waters without significantly impacting your overall deliverability metrics. If these re-engagement attempts yield positive results, you can gradually increase the volume, but always keeping a close eye on your engagement and complaint rates. This strategy minimizes the risk of sending to inactive users.

Maintaining a clean email list is an ongoing process, not a one-time event. Regularly identifying and either re-engaging or sunsetting inactive contacts is a deliverability best practice. This helps ensure that you are primarily sending to engaged recipients, which positively reinforces your sender reputation and improves your chances of landing in the inbox. Remember, a smaller, highly engaged list is far more valuable for your deliverability than a large list filled with inactive or problematic addresses.

Aggressive clean-up

Definition: Marking contacts as inactive after only 1 month of no engagement.
Impact: High risk of removing genuinely interested subscribers who simply don't open all emails. Can lead to lost revenue and customer relationships.
Perception: May be perceived by ISPs as a tactic used by spammers who rapidly discard non-responsive addresses, negatively impacting domain reputation.

Gradual re-engagement

Definition: Gradually reducing email frequency or targeting after 3-6 months of inactivity.
Impact: Allows time for occasional logins or delayed engagement. Preserves potential customer relationships while mitigating deliverability risks.
Perception: Seen as responsible list management by ISPs, contributing positively to sender reputation.

Avoiding blacklists and maintaining list health

One of the primary goals of managing inactive contacts is to prevent your domain or IP from ending up on an email blacklist (or blocklist). These lists are databases of IP addresses and domains known to send spam, and once on them, your emails will be blocked by many major mailbox providers. Sending to a high percentage of inactive contacts, especially those that may have become spam traps or simply generate complaints, significantly increases this risk. Proactive list hygiene is your best defense.

Regularly cleaning your email list involves identifying and removing addresses that are causing problems, such as hard bounces or repeated non-engagement. This process can be daunting, but it is essential for maintaining a healthy sending reputation. It's not just about removing addresses, but about understanding the different types of inactive contacts and the specific risks they pose. For example, Yahoo/AOL email addresses might behave differently than Gmail addresses when it comes to inactivity and bounces.

Furthermore, a sudden spike in negative metrics, even from a single campaign to inactive contacts, can have a ripple effect on your entire email program. Mailbox providers often apply stricter filtering to senders with erratic sending patterns or sudden drops in engagement. This means your otherwise good emails could also start landing in spam folders. Consistent monitoring of your deliverability metrics and proactive list management are key to avoiding these pitfalls and ensuring your messages consistently reach the inbox.

Views from the trenches

Best practices

Implement a gradual re-engagement strategy for inactive contacts, introducing small segments over time to gauge response and minimize risk.

Define inactivity thresholds based on your specific audience behavior and email frequency, rather than generic timelines.

Prioritize list hygiene by regularly removing hard bounces and contacts that consistently show no engagement after multiple re-engagement attempts.

Common pitfalls

Sending large, untargeted campaigns to deeply inactive segments, leading to spikes in spam complaints and hard bounces.

Defining inactivity too aggressively (e.g., one month), which can prematurely remove potentially valuable subscribers.

Neglecting to monitor post-campaign engagement metrics for re-engagement efforts, missing crucial signals of deliverability issues.

Expert tips

Consider a multi-stage re-engagement approach, starting with very low-frequency emails before increasing the sending volume.

Utilize engagement tiers to slowly reduce sending frequency to less active subscribers, instead of a binary active/inactive split.

Be prepared to 'sunset' (remove) contacts who show no response to re-engagement efforts to protect your sender reputation.

Expert view

Expert from Email Geeks says the impact of sending to inactive contacts depends on how inactive they are, suggesting that mixing campaigns with already engaged senders can help average out metrics.

September 1, 2021 - Email Geeks

Expert view

Expert from Email Geeks says focus on the number of recipients rather than the number of campaigns. Mixing a very small number of inactives with well-engaged streams should have a negligible effect, but a large campaign to mostly inactives can lead to problems.

September 1, 2021 - Email Geeks

The path to better deliverability

Sending emails to inactive contacts, while seemingly a way to broaden your reach, can significantly jeopardize your email deliverability. The primary threats include a degraded sender reputation, increased risk of hitting spam traps, and higher bounce rates, all of which can lead to your legitimate emails landing in the spam folder or being rejected.

Effective management of inactive subscribers requires a nuanced approach. It starts with a well-defined understanding of what inactivity means for your audience, followed by careful segmentation. For those you wish to re-engage, a gradual, low-volume strategy is paramount to avoid sudden negative impacts on your sending metrics.

Ultimately, a healthy email program is built on a foundation of engagement and trust. Prioritizing a clean, active email list over sheer volume will yield far better deliverability rates and ensure your messages consistently reach their intended recipients. Regularly cleaning your list and strategically managing inactive contacts are not just best practices, but essential components of a successful email strategy.