What is email marketing and why does it still deliver the highest ROI?
Email marketing is a direct communication channel where brands send messages to subscribers who have opted in to receive them. Unlike paid media, email delivers content to an owned audience without platform fees or algorithmic suppression.
The channel consistently outperforms other digital tactics. In February 2025, 26.9% of UK and US marketers said email delivered their best ROI, ahead of websites and blogs (22.7%), SEO (19.2%), paid search (16.1%), and social media advertising (11.4%), according to GetResponse. Email also requires modest investment: only 12% of marketers worldwide allocate more than 15% of their budgets to email, while 22% allocate less than 5%, according to a Litmus survey. Consumer preference reinforces the channel's value: 59% of adults worldwide say email is their preferred format for receiving offers and updates, according to a Woo and Klaviyo survey.
This combination of cost efficiency, direct access, and consumer preference explains email's durability despite decades of predictions about its decline.
Why is email becoming more critical as zero-click search grows?
Google's AI Overviews and featured snippets increasingly answer user queries without requiring a click to a website. Zero-click searches now account for 69% of Google queries, up from 56% a year earlier, according to Similarweb's July 2025 report.
For marketers, this shift reduces the value of organic search as a traffic source. Content that once drove website visits now gets summarized and consumed without attribution. Organic click-through rates drop 61% for queries where Google AI Overviews appear, according to Seer Interactive.
This makes owned channels like email strategically essential. Unlike search traffic, email subscribers represent a direct relationship that platforms cannot intermediate. Brands that invest in list growth and engagement gain independence from algorithm changes and AI-driven content summarization.
How are AI agents changing email consumption?
AI is moving from a marketer's tool to an inbox gatekeeper. Google's experimental AI agent, CC, delivers daily email briefings that summarize information from Gmail, Calendar, and Drive, deciding what matters and surfacing it first. ChatGPT's Pulse offers similar morning updates using chat history and user preferences.
This shift means AI systems become the first reader, editor, and sorter of messages. Google has an advantage because it already owns email, calendars, and storage, giving CC deep context and tight ecosystem control.
For marketers, the implication is significant: subject lines and preview text may no longer determine whether messages get attention. AI assistants will decide what's worth surfacing based on relevance, sender reputation, and user behavior patterns. Brands that over-email or deliver low-value content risk being filtered out before recipients see them. Optimizing for AI agents, not just inboxes, will become a priority in 2026.
What new deliverability rules are Big Tech enforcing on bulk email senders?
Google, Yahoo, and Microsoft have implemented strict requirements for anyone sending more than 5,000 emails daily. These standards require three key criteria: proper authentication (SPF, DKIM, DMARC), low spam complaint rates, and one-click unsubscribe options. Their bulk mail controls are effectively impossible to overcome without compliance.
The stakes are high given market concentration. Gmail (72.1%), Microsoft Outlook (33.7%), Yahoo Mail (20.3%), and Apple Mail (7.4%) make up the majority of mailbox providers used by email marketers worldwide, per Sinch. 60.3% of US marketers consider spam filtering their biggest deliverability challenge, according to a Kickbox survey.
These changes shift power from senders to recipients, similar to Apple Mail's 2021 privacy update. Marketers must audit domain authentication, enable easy unsubscribe links, and monitor spam rates. Legacy tools may still work for basic needs, but without modern infrastructure and cleaner lists, brands risk getting blocked entirely.
Why are consumers unsubscribing from brand emails at higher rates?
Message overload is driving consumer backlash. 40% of US consumers unsubscribe from brand emails or texts weekly, according to GetApp.Consumers unsubscribe due to too many messages (60%), overly sales-driven content (44%), and repetitive or generic content (36%), according to a Woo and Klaviyo survey.
Gmail's new “Manage Subscriptions” tool accelerates this trend by letting users unsubscribe from promotional emails in bulk. Brands that send most frequently appear at the top of the list, magnifying churn risk.
Trust concerns compound the problem. 67% of US adults avoid responding to emails because messages may be spam or a scam, according to a YouGov survey. This caution is warranted, as 61% of US adults said they’ve experienced an email scam attempt, per Google and Morning Consult.
Brands already using segmentation and frequency controls will see less fallout, while those with poor targeting face accelerated list erosion.
What drives email engagement in 2026?
Clear calls-to-action remain the most effective engagement driver. 35% of marketing professionals worldwide say interactive buttons or CTAs are the most effective elements in emails, according to Litmus. Interactive forms (14%), surveys, polls, and quizzes (13%), and countdown timers (12%) follow.
The top KPI for marketing emails is click-through rate, cited by 29% of marketing professionals, followed by conversion rate (24%) and revenue generated (17%), according to Litmus. Nearly a quarter (23%) report CTRs above 5%, while the majority fall below that threshold.
This data suggests marketers should prioritize clean, prominent CTAs and test placement, color, and copy to identify what drives action. For campaigns requiring deeper interaction, layering in forms or countdown timers can help, but leading with a button remains the baseline.
The most useful forms of personalization are based on stated preferences (42%), name (31%), and past purchases (29%), according to a Sinch survey. Personalization improves results, but only when paired with clear value and appropriate frequency.
How are marketers using AI to improve email campaigns?
AI has moved from experimental to operational. Email marketing (51%) is where AI is most used for content creation, ahead of social media and website content, according to a HubSpot survey. Copy and image generation are the most common AI use cases (25%), followed by personalization (18%), campaign analysis (16%), and send-time optimization (14%), according to a Litmus survey.
Production timelines have shortened dramatically. Only 6% of marketers required two weeks or more to produce an email in 2025, up from 62% in 2024, per Litmus. AI addresses three persistent email challenges:
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Personalization at scale. AI segments audiences, optimizes send times based on recipient behavior, and customizes content beyond surface-level name insertion.
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Reengagement. AI identifies customers at varying purchase stages in real time, enabling targeted messages that boost conversions and retention.
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Testing sophistication. 57% of marketers worldwide use A/B testing within email, according to Ascend2. AI expands testing scope by creating more variants, identifying patterns across segments, and analyzing results more thoroughly.
Adobe's Marketo Engage update in May 2025 expanded its new Email Designer with features like AI-powered email design with cloning, GenStudio integration, and improved content reuse, streamlining production for time-constrained teams. Despite these advances, oversight remains essential. Marketers should review AI-generated copy and audience segments for accuracy before deployment.
How should email marketers adapt their strategy for 2026?
The environment demands discipline over expansion. 60% of US small businesses plan to raise marketing spend in 2026, but budgets are moving toward channels with strong attribution, per Clutch. Email with CRM integration fits this profile. 44% of SMBs cited email as their most effective marketing channel in 2025, nearly double the prior year, according to a Constant Contact survey.
Four priorities should guide 2026 strategy:
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Sharpen segmentation to match subscriber intent. Use stated preferences, behavioral data, and lifecycle indicators to deliver relevant content.
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Shift email content from volume to value. With AI agents filtering inboxes and Gmail enabling batch unsubscribes, low-value messages face faster deletion. Replace frequent promotional sends with high-value content: educational updates, loyalty messaging, and lifecycle guidance.
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Strengthen authentication and sender identity. Audit SPF, DKIM, and DMARC authentication. Monitor spam complaint rates. Maintain clear and consistent sender information and recognizable branding to reassure subscribers.
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Optimize for AI summarization. Front-load key information in email copy. AI systems prioritize content from the lede when generating summaries. Catchy subject lines alone will not guarantee visibility.
We prepared this article with the assistance of generative AI tools and stand behind its accuracy, quality, and originality.
EMARKETER forecast data was current at publication and may have changed. EMARKETER clients have access to up-to-date forecast data. To explore EMARKETER solutions, click here.