What Is Email Marketing?
By Mark Gabrielli · Fractional CMO & COO · Last updated: May 2026Email marketing is the use of email to promote products and services, nurture leads through buying cycles, retain customers, and build ongoing relationships with a defined audience through targeted, personalized communications. Email consistently delivers the highest ROI of any digital marketing channel -- the average return on email marketing investment is $36 to $42 for every $1 spent -- because it reaches an opted-in audience that has already expressed interest, at near-zero marginal cost per message. For B2B companies with multi-month buying cycles, email marketing is the primary channel for maintaining engagement with leads who are not yet ready to buy, ensuring the company stays top-of-mind until the prospect reaches purchase readiness.
Email marketing is the use of email to promote products and services, nurture leads through buying cycles, retain customers, and build ongoing relationships with a defined audience through targeted, personalized communications.
How Email Marketing Works
Email marketing operates through two distinct modes: broadcast email (newsletters, announcements, and campaigns sent to a full list or segment) and triggered email (automated sequences sent to individuals based on their behavior or stage). Broadcast email builds audience relationships and drives one-time actions; triggered email nurtures leads through the buying journey with contextually relevant content delivered at the right moment. The highest-performing email marketing programs use both modes strategically -- triggered sequences for lead nurture and onboarding, broadcast campaigns for thought leadership, product updates, and time-sensitive offers.
Email deliverability is the foundation of effective email marketing -- if emails do not reach the inbox, nothing else matters. Deliverability depends on sender reputation (domain and IP reputation built through consistent sending practices), list hygiene (removing invalid addresses and unengaged subscribers), authentication (SPF, DKIM, and DMARC records), and engagement rates (high open rates signal to inbox providers that the sender's email is wanted). Companies that grow email lists without proper hygiene practices and authentication configuration consistently experience declining deliverability that undermines the entire program.
Email is the only marketing channel where you own the audience -- social platforms can change their algorithms, ad costs can spike, and SEO rankings can fluctuate, but your email list belongs to you.
Core Components of Email Marketing
- Email List Building and ManagementGrowing an opted-in subscriber base through content offers, lead magnets, event registrations, and website sign-up forms -- with proper list segmentation, hygiene practices, and preference management to maintain engagement and deliverability.
- Email Automation and Nurture SequencesMulti-step automated sequences triggered by subscriber actions or stages: welcome sequences for new subscribers, lead nurture for MQLs, onboarding sequences for new customers, and re-engagement sequences for inactive subscribers.
- Email Newsletter and Broadcast CampaignsRegular broadcast emails to the full list or segments: newsletters with industry insights, product updates, promotional campaigns, event invitations, and thought leadership content that maintains audience engagement over time.
- Segmentation and PersonalizationDividing the email list into segments based on demographics, behavior, purchase history, and engagement -- and personalizing email content, subject lines, and send timing to each segment to improve relevance and engagement rates.
- Deliverability ManagementMaintaining sender reputation through domain authentication (SPF, DKIM, DMARC), list hygiene (regular removal of invalid and unengaged addresses), and engagement monitoring -- ensuring emails consistently reach the inbox rather than spam.
- Email Analytics and A/B TestingTracking open rates, click-through rates, conversion rates, unsubscribe rates, and revenue attribution by campaign and sequence -- with A/B testing of subject lines, content, send times, and CTAs to continuously improve performance.
How MarkCMO Approaches This
MarkCMO email marketing engagements begin with a deliverability audit: verifying that domain authentication (SPF, DKIM, DMARC) is properly configured, reviewing list health and engagement rates by segment, and identifying any existing automation sequences that have configuration errors. A significant percentage of companies with email deliverability problems have misconfigured authentication that can be fixed in hours.
Once deliverability is confirmed, MarkCMO builds or rebuilds the email program: a newsletter editorial calendar, the lead nurture sequences mapped to the buyer journey, and the triggered automation workflows tied to CRM stage and behavior data. Email marketing is measured at the revenue level -- not just opens and clicks.
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See Email Marketing Services →Frequently Asked Questions
Email marketing is the use of email to communicate with prospects, leads, and customers -- promoting products and services, nurturing leads through buying cycles, onboarding new customers, and building ongoing audience relationships. Email marketing includes broadcast campaigns (newsletters, promotions) and triggered automation sequences (lead nurture, onboarding, re-engagement). With an average ROI of $36 to $42 per $1 spent, email consistently delivers the highest return of any digital marketing channel.
Email deliverability is the ability to successfully deliver emails to recipients' inboxes rather than spam folders or rejection. Deliverability depends on sender reputation (domain and IP reputation built through consistent practices), authentication (SPF, DKIM, and DMARC records correctly configured), list quality (low bounce rates and high engagement), and content quality (avoiding spam trigger words and excessive links). Poor deliverability can quietly undermine an entire email program -- emails that land in spam are invisible even to engaged subscribers.
Email marketing is one channel within the broader marketing automation ecosystem. Marketing automation platforms manage email marketing alongside lead scoring, CRM integration, behavioral tracking, and multi-channel workflow automation. Email marketing in isolation focuses on the email channel specifically. Marketing automation integrates email with website behavior, CRM data, and other channels to trigger contextually relevant communications based on the individual's journey -- producing more personalized and effective email than standalone email marketing allows.
Average B2B email open rates (measuring as of 2025, using click-based proxies due to Apple Mail Privacy Protection) range from 20 to 40 percent. Average click-through rates range from 2 to 5 percent for broadcast emails and 5 to 15 percent for targeted automation sequences. Industry, audience quality, and subject line effectiveness vary these benchmarks significantly. The most important metrics are trends over time and conversion to pipeline -- not absolute open or click rates compared to industry averages.
B2B email list growth strategies: (1) Gated content offers -- research reports, templates, calculators, and guides that require email registration; (2) Webinar and virtual event registrations; (3) Newsletter opt-in on blog and website -- with clear value proposition for subscribing; (4) LinkedIn content promotion driving to email-gated resources; (5) Paid social campaigns driving to lead magnet landing pages; (6) Partner co-marketing -- joint content with complementary brands cross-promoting to each other's audiences. List quality matters more than size -- an engaged 5,000-person list outperforms an unengaged 50,000-person list.