Email Glossary
Clear definitions of the email, deliverability, and marketing terms that matter.
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- Click-Through RateClick-through rate (CTR) is the percentage of email recipients who click on one or more links within an email message. It is calculated by dividing the total number of clicks by the total number of emails delivered, then multiplying by 100.
- Complaint RateThe percentage of emails marked as spam or reported as unwanted by recipients, calculated as complaints divided by total emails delivered. A key indicator of sender reputation and list quality.
- Conversion FunnelA visual model that tracks how subscribers progress through a series of stages—from awareness to action—such as landing on a page, opening an email, clicking a link, and completing a purchase. It helps identify where prospects drop off and which touchpoints are most effective at moving people toward a goal.
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- DeliverabilityDeliverability is the ability of a marketing email to reach a recipient's inbox without being filtered, blocked, or rejected by email service providers. It measures how successfully your messages arrive at their intended destination rather than bouncing or landing in spam folders.
- Drip CampaignA drip campaign is a series of automated emails sent to subscribers over a set period of time based on specific triggers or schedules. It delivers targeted content gradually to nurture leads, build relationships, and guide prospects through the customer journey.
- Dynamic Content BlockA segment of email content that automatically changes based on recipient attributes, behavior, or preferences, allowing a single email template to deliver personalized messages to different audiences. Dynamic content blocks adjust in real time without requiring separate email sends.
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- Email PersonalizationEmail personalization is the practice of tailoring message content, subject lines, and send times to individual recipients based on their data, behavior, and preferences. It goes beyond addressing someone by name to dynamically inserting relevant information that speaks directly to each subscriber.
- Engagement MetricsEngagement metrics are quantifiable measurements that track how recipients interact with your email campaigns, including opens, clicks, replies, and forwards. They reveal whether your content resonates with your audience and drive decisions about campaign optimization.
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- List DecayList decay is the natural decline in email list quality and engagement over time as subscribers become inactive, change email addresses, or lose interest. It occurs even with a well-maintained list and directly impacts deliverability, open rates, and overall campaign performance.
- List SegmentationList segmentation is the practice of dividing your email subscriber base into smaller, targeted groups based on shared characteristics, behaviors, or interests. This allows you to send more relevant, personalized messages to each segment instead of broadcasting identical content to your entire list.
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- Sender ReputationSender reputation is a score or assessment assigned to your email sending domain and IP address by mailbox providers, based on historical email behavior and engagement metrics. It directly influences whether your emails reach the inbox, spam folder, or are rejected entirely.
- Send Time OptimizationSend Time Optimization (STO) is a technique that automatically determines and schedules email sends at the time each individual recipient is most likely to open and engage with a message. It uses historical engagement data and behavioral patterns to maximize open rates and click-through rates.
- SMTP RelayA mail server or third-party service that accepts outgoing emails from your application or system and forwards them to the recipient's mail server on your behalf. SMTP relays simplify email infrastructure by handling authentication, routing, and delivery logistics.
- Spam FilterA spam filter is an automated system that identifies and blocks unsolicited or malicious emails before they reach a recipient's inbox. These filters use machine learning, rule-based algorithms, and reputation databases to distinguish legitimate messages from spam, phishing attempts, and other unwanted content.
- Suppression ListA suppression list is a database of email addresses that should not receive future campaign communications due to previous unsubscribes, complaints, bounces, or other business rules. Maintaining an accurate suppression list is essential for protecting sender reputation and ensuring compliance with email regulations.