How does pruning your email list affect sender reputation?

Pruning helps by removing unengaged or invalid email addresses from your list. Sending to these addresses can lead to high bounce rates, increased spam complaints, and lower engagement, all of which negatively impact your sender reputation. A cleaner list signals to ISPs (Internet Service Providers) that your content is relevant and wanted, improving your inbox placement.

While opens and clicks are common metrics, ISPs look at a broader range of signals. These include whether recipients move your email to the primary inbox, reply, forward, or mark it as spam. Factors like Apple Mail Privacy Protection can also skew reported open rates, so relying solely on opens can be misleading.

What is the recommended process for pruning inactive subscribers?

Before removing subscribers, it is best to segment inactive users and send them a re-engagement campaign. This typically involves a series of emails asking if they still wish to receive your content. If they don't respond after these efforts, then it's generally safe to remove them.

How often should I prune my email list?

The ideal frequency depends on your sending volume and list decay rate. Many email marketers prune their lists every 6 to 12 months, or after specific campaigns. However, continuous monitoring of engagement and bounce rates should inform your pruning schedule.

Does pruning apply differently to marketing emails versus newsletters?

Not necessarily. If your emails are primarily content-based newsletters (e.g., informative articles, personal blogs) that recipients might read without clicking, direct engagement metrics might not fully capture their interest. Consider other factors like website visits or direct replies, and always offer a clear re-engagement option.

Does pruning your email lists help with deliverability? - Sender reputation - Email deliverability - Knowledge base

The question of whether pruning your email lists helps with deliverability is a common one, and it is crucial for anyone involved in email marketing. On the surface, it seems counterintuitive to intentionally reduce your subscriber count, especially when growth is often the primary goal. However, in the world of email, quality often trumps quantity when it comes to reaching the inbox.

I've learned that maintaining a healthy, engaged email list is one of the most effective strategies for ensuring your messages consistently land in recipients' inboxes. Pruning isn't about simply cutting subscribers, it's about optimizing your sending practices to improve engagement and avoid signals that could harm your sender reputation.

Impact on sender reputation

Pruning your email list significantly impacts your sender reputation. When you send emails to unengaged or invalid addresses, it can lead to higher bounce rates, increased spam complaints, and lower engagement metrics like open and click-through rates. Internet Service Providers (ISPs) closely monitor these signals.

A list filled with inactive subscribers can dilute your overall engagement rates. If a large percentage of your emails are not opened or clicked, ISPs might interpret this as a sign that your content is not relevant or, worse, unwanted. This can lead to your emails being directed to the spam folder or even being blocklisted (blacklisted).

The impact of a high bounce rate

Google and other ISPs view high bounce rates, particularly hard bounces, as a strong negative signal. It indicates that you might be sending to old, invalid, or non-existent email addresses, which can lead to your IP address or domain being flagged. Regularly removing such addresses is crucial for maintaining a healthy sender reputation. For more on improving your domain reputation, consider using tools like Postmaster Tools.

Beyond bounce rates, a critical reason to prune is to avoid spam traps. These are email addresses specifically designed to catch spammers. Sending to a spam trap can immediately land your domain or IP on a blocklist (or blacklist), severely impacting your deliverability. Pruning helps minimize your exposure to these hidden threats, preserving your email domain reputation.

Ultimately, a cleaner list sends a positive signal to ISPs, demonstrating that you are a responsible sender who values engagement. This proactive list hygiene improves your overall sender reputation, increasing the likelihood of your emails reaching the inbox.

The nuance of engagement

The definition of engagement is a subtle yet critical aspect of list pruning. While marketers often rely on metrics like opens and clicks, ISPs (like

Yahoo! Mail and

Gmail) employ more sophisticated signals that aren't always visible to senders. For instance, Apple Mail Privacy Protection (MPP) can show inflated open rates because it prefetches emails, making it difficult to accurately gauge true engagement based on opens alone. This also applies to other email providers who prefetch or proxy content, as discussed in this Validity article.

I've also seen instances where subscribers read newsletters directly in their email client without triggering tracking pixels, or they use RSS readers. These are genuinely engaged recipients, but they might appear inactive based on standard metrics. Removing these subscribers could mean losing valuable readership, so it is important to understand the complexities of engagement measurement.

Sender's engagement metrics

Tracked Opens: Relies on tracking pixels, susceptible to prefetching (e.g., Apple MPP).
Clicks: Indicates direct interaction but not all readers click links.
Website Activity: How subscribers interact with your brand outside of email.

ISP's engagement signals

Inbox Placement: Whether recipients move emails to primary inbox or not.
Replies and Forwards: Direct interaction showing high interest.
Spam Complaints: Explicit negative feedback, highly damaging.

This highlights the need for a nuanced approach. While traditional engagement metrics provide valuable insights, they should not be the sole basis for list pruning. Consider your content type, as marketing emails often have different engagement goals than content-based newsletters.

Instead of immediately removing subscribers based on perceived inactivity, I recommend implementing re-engagement campaigns. These campaigns serve to confirm whether subscribers still wish to receive your emails, providing a clear positive or negative signal. This approach respects your audience and helps you make informed decisions about your list, which contributes to better deliverability and open rates.

Practical steps for list pruning

Implementing an effective list pruning strategy involves several practical steps. First, it's essential to define what inactive means for your specific sending habits. This might involve looking at a combination of factors over a defined period, such as 90 to 120 days without opens or clicks. For some businesses, particularly seasonal ones, this timeframe may need to be adjusted.

Once you've identified potentially inactive subscribers, segment them into a separate group. Before removing them, send a re-engagement campaign. This sequence of emails can include messages asking if they still want to hear from you, offering exclusive content, or reminding them of the value you provide. The goal is to elicit a clear signal of continued interest or disinterest.

Pruning strategy	Description	Impact on deliverability
Time-based pruning	Removing subscribers inactive for X months (e.g., 6-12 months). Simple to implement.	Reduces emails to unresponsive addresses, improving overall list health.
Engagement-based pruning	Removing those with no opens or clicks over a period, after re-engagement efforts.	Targets truly unengaged users, boosting key performance indicators like open rates.
Bounce/error-based removal	Immediately removing hard bounces and addressing soft bounces quickly.	Prevents damage to sender reputation and avoids spam traps. Essential for improving deliverability.

For subscribers who still don't respond after re-engagement efforts, it is generally safe to remove them. This process is not a one-time task but an ongoing aspect of list hygiene. Regularly evaluating and cleaning your list ensures that you're only sending to an audience that genuinely wants to hear from you.

By actively managing your list and removing unengaged or invalid addresses, you conserve sending resources, reduce costs, and most importantly, improve the overall health and effectiveness of your email program. Remember, a smaller, more engaged list will always outperform a large, disengaged one in terms of deliverability and return on investment.

Views from the trenches

Best practices

Actively manage your email list by regularly identifying inactive subscribers and bad addresses.

Implement re-engagement campaigns to confirm subscriber interest before removing them from your main list.

Segment your list based on engagement levels to tailor content and preserve deliverability.

Prioritize removing hard bounces and addressing soft bounces promptly to maintain list health.

Use historical data on recipient behavior to make informed decisions about pruning thresholds.

Common pitfalls

Blindly applying generic "best practices" for pruning without considering your specific audience or content type.

Relying solely on open rates as an engagement metric, especially with Apple MPP and other proxy effects.

Not implementing re-engagement campaigns before removing inactive subscribers, potentially losing interested readers.

Ignoring negative signals like spam complaints or high bounce rates from unengaged segments.

Neglecting to consistently monitor and clean your email list, allowing it to decay over time.

Expert tips

For marketing emails, engagement-based pruning is crucial for conversion and deliverability.

Newsletters might have different engagement rules; consider readers who don't click but still consume content.

Focus on negative signals (unsubscribes, complaints) more than perceived inactivity for pruning decisions.

If migrating to a new platform, a list cleaning before import is highly recommended.

Be cautious when interpreting engagement data due to factors like prefetching and email client settings.

Marketer view

Marketer from Email Geeks says list hygiene is fundamental, as a list heavy with unengaged subscribers can negatively influence metrics with certain filters. They also suggested segmenting non-engagers for win-back campaigns.

2023-06-21 - Email Geeks

Expert view

Expert from Email Geeks says pruning helps because removing contacts without positive engagement signals means mail filters see a higher percentage of their users engaging with your mail, leading to more positive filtering decisions.

2023-06-21 - Email Geeks

Final thoughts on list pruning

In conclusion, pruning your email lists is indeed a beneficial practice for improving deliverability. It's a key component of effective email list hygiene that helps optimize your sender reputation and ensures your messages reach genuinely interested subscribers. By removing inactive or invalid contacts, you reduce bounces, avoid spam traps, and enhance overall engagement metrics that ISPs use to evaluate your sending practices.

However, the process requires a thoughtful, data-driven approach. It is not about mindlessly cutting subscribers but about understanding engagement signals beyond simple opens and clicks, especially with the complexities introduced by features like Apple MPP. Implementing re-engagement strategies allows you to make informed decisions, ensuring you maintain a vibrant, high-quality list that consistently lands in the inbox.