Email List Growth Strategies That Deliver Results in 2025

In 2025, email remains the single most powerful revenue and retention channel you can own. 

According to Forbes, every $1 invested in email marketing returns approximately $36, offering a staggering 3,600% ROI. In fact, 59% of consumers say email is their preferred way to hear from brands, which is more than three times the number who prefer social media (18%).

However, there’s always the risk of overuse and privacy concerns. Around 37% of consumers say email becomes the most frustrating channel when brands flood their inboxes with too many messages.

Complicating matters are rising ad fatigue and climbing customer acquisition costs. 

Gartner reports that marketing budgets have remained flat at just 7.7% of company revenue in 2025, leaving little room for costly tactics.

From the brand’s perspective, this means tightening its marketing focus and rethinking priorities, one where you own the audience (and the inbox).

This guide highlights five email list growth strategies from high-growth brands, each with actionable tips and best practices you can make your own. Let’s go!

How to Grow Email List: Learn from 5 Fast-Growing Brand Examples to Get Your Strategy Going

Brands can’t afford to take a one-size-fits-all approach to boosting their email list growth. 

Partly because privacy regulations (like Apple’s App Transparency feature) are tightening, and consumers are becoming more context-aware. The road to success is rethinking acquisition from the ground up. This includes blending channels, personalizing in real time, and optimizing every touchpoint for conversion.

In this round-up, we spotlight five brands that are doing it right, using smart email list growth strategies to turn everyday interactions into high-value opt-ins and transform email into a true growth engine.

Use Case #1: Promod Achieved 38X ROI with Smart Audience Segmentation

Business Challenge: Promod required a solution to manage high-volume campaigns in four languages (English, French, Spanish, and German) while maintaining relevant content and high performance.

Strategy #1: Insider’s “Email” Feature Drove Smarter Audience Segmentation and Localization

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Insider’s email builder enabled the team to create dynamic blocks that adapted to region, language, and user engagement level. This allowed the team to send one intelligently segmented campaign instead of managing dozens of versions. 

Key Learnings:

• Use dynamic content blocks to localize at scale
• Segment by engagement to protect deliverability and reduce opt-outs
• Automate win-back flows based on the last open and click instead of time-lapsed
• Maintain a modular campaign structure for faster localization rollouts
• A/B test content variations by region or language group
• Leverage historical engagement data to prioritize high-value segments

Results:

• 3X higher open rates vs industry benchmarks
• 99% email delivery rate

Want to try dynamic content in your next campaign?

Explore Insider’s Email platform now

Bonus: Learn about 9 Last-Minute Email Deliverability Tips for Holiday Season Success

Strategy #2: Orchestrate Multi-Country Journeys with Email as the Anchor

Promod also wanted to replicate and expand its legacy customer journeys, such as birthday messages, cart reminders, etc., across 10 countries.

Insider’s “Architect” Feature in Action

Insider’s Architect enabled one workflow to trigger email, app push, and SMS automation across regions, all customized by event type and audience segment:

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Key Learnings:

• Build one journey framework and deploy everywhere
• Use email as the core touchpoint, with supporting channels
• Test journey branches easily; no developer support is required
• Centralize journey management to reduce duplication and manual errors
• Incorporate culturally relevant touchpoints and timing
• Layer in behavioral conditions for smarter automation

Result: 38x ROI in under 12 months

Client Insight

We made the strategic choice to start with the one BU (France), and once France was perfectly implemented, we duplicated what was done for the other BU, allowing us to move fast without compromising on Quality. Promod now manages multi-domain operations seamlessly across 10 countries using Insider’s platform.

         — Ludovic Lefevre, IT Domain Manager

Want to see Architect in action? Request a demo now! 

Use Case #2: Riviera Maison Achieved a 2.53X Increase in Revenue Per Visitor with Personalized Email Flows

Business Challenge: Riviera Maison needed to lift on-site engagement and convert casual browsers into high-intent shoppers. They wanted to create moments that felt timely, relevant, and worth clicking into.

Strategy: Insider Helped Launch Timely Onsite Messages and Personalized Email Flows Tied to Customer Activity

The brand moved beyond batch-and-blast campaigns. Instead, the team built audience segments tied to behavioral triggers such as recent visits, scroll depth, and exit intent.

Note that these weren’t just promotional pushes. Each message was intentionally created to provoke action by speaking to where the customer was in their journey:

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Key Learnings:

• Use scroll-depth, time-on-site, and returning visitor logic to trigger email collection and exit offers
• Try Insider’s Modular Email Editor to build dynamic, responsive emails in minutes using intuitive drag-and-drop controls that feel more like assembling building blocks than writing code
• Follow up with a custom email flow that references exactly what they saw and browsed
• Use urgency and scarcity tactics in follow-up emails
• Sync on-site behavior with email content in real time

Result: 4.6X increase in click-through rates

With tailored email campaigns and targeted messaging, we kept our customers engaged and significantly improved our click-through rates.

           — Elisabeth Hovius, Head of Marketing & Digital Commerce, Riviera Maison

Want to build high-performing segments and campaigns while keeping ops work to a minimum? Explore how Agent One simplifies audience building using autonomous AI.

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Use Case #3: Remix Increased First Purchases by 104% with Guided Onboarding Journeys

Business Challenge: Remix was successfully attracting new users to register on their platform; however, many failed to make a purchase after registration. The brand needed a seamless way to convert this interest into actual revenue while avoiding discounts and heavy retargeting.

Strategy: Insider Helped Build a Guided, Behavior-Based Onboarding Flow to Nudge First Purchases

Instead of sending generic welcome emails, Remix worked with Insider to design a behavior-driven onboarding journey. This automated flow adapted based on user actions post-registration.

The journey included:

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• Email 1 (1 week after registration): Prompted users to save their preferred search filters to receive more relevant results
• Email 2: Guided users to favorite brands they love, unlocking personalized recommendations and boosting platform stickiness
• Email 3: Explained how to combine orders to save on shipping, removing a key friction point and encouraging checkout

By helping users engage more deeply with the platform, Remix nurtured intent.

Key Learnings:

• Create onboarding emails that teach (and don’t simply sell)—use progressive disclosure to guide users toward value
• Trigger communications based on inactivity windows, such as 7 days after signup, with no purchase made
• Emphasize non-monetary benefits (such as personalization, convenience, and platform features) to establish trust early
• Add buttons, carousels, or preference selectors directly within emails to increase engagement and encourage users to personalize their experience without leaving their inbox
• Identify which new users are most likely to convert based on early actions (e.g., brand follows, search activity), and tailor onboarding paths accordingly to maximize ROI

Results:

• 104% increase in first purchases compared to the previous quarter
• 22.23% uplift in conversion rate from registered users

Use Case #4: All Nutrition Drove 12.67% of Total Revenue with Automated Email Campaigns

Business Challenge: All Nutrition needed a smart and scalable strategy to re-engage potential customers, boost conversions, and turn interest into action.

Strategy: Insider Helped Launch Personalized, Automated Email Campaigns to Re-Engage and Convert

Instead of relying on generic retargeting, All Nutrition worked with Insider’s digital growth consultant to build segmented email flows that felt personal and timely:

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This included:

• Automated re-engagement sequences for users who left the site before making a purchase
• Dynamic newsletters tailored to user behavior and preferences
• Email content that aligned with seasonal trends and product interests

The key wasn’t volume, it was relevance. Each campaign was built around where the customer left off in their journey, and what they were most likely to respond to next.

Key Learnings:

• Use personalized newsletters to keep your brand top of mind and drive repeat visits
• Segment users based on on-site behavior, like products viewed or cart abandoned, for higher open and click rates
• Build automated win-back flows for bounce and exit events to recover lost traffic with minimal lift
• Adjust the timing and frequency of emails based on where users are in their journey (e.g., first-time visitor vs. loyal customer) to avoid fatigue and maximize engagement

Results:

• 21% email opt-in rate
• 1.7X higher conversion rate from email versus site average
• 12.67% of total revenue attributed to Insider-powered email campaigns in just 3 months

Client Insight

Working with Insider has been rewarding. The team is very focused on service and looking for continuous improvements. They have a very valuable strategic analytical approach that results in continuous proposals on how to take advantage of Insider’s tools and improve your business results.

              — Cesar Esposito, General Manager

Use Case #5: Slazenger Achieved 49X ROI with Targeted Price Drop Notifications

Business Challenge: Slazenger sought to enhance email click-through and conversion rates, particularly among customers who were browsing but not making a purchase, especially those sensitive to pricing. The challenge was to re-engage these users with personalized, relevant messaging.

Strategy: Insider Helped Slazenger Target Price-Sensitive Shoppers with AI-Powered Discount Alerts

Using Insider’s Architect and Smart Segment Creator, powered by Sirius AI, Slazenger identified users with a high affinity for discounts, those most likely to act on price drops.

They then launched automated journeys that triggered email and web push notifications within 24 hours whenever a product a user had viewed, wishlisted, or abandoned dropped in price by 10% or more:

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This smart targeting approach ensured that only users with true price sensitivity received discount alerts, keeping margins intact while driving conversions.

Key Learnings:

• Use predictive segments (like High Discount Affinity) to identify users most likely to act on price drops
• Set up automated alerts tied to user-specific product interactions, views, wishlist adds, and cart abandonments
• Combine email with web push to boost urgency across multiple channels rather than relying solely on inbox visibility
• Instead of blasting price drop emails to your entire list, use AI to focus only on users showing strong purchase signals and discount-seeking behavior, preserving profitability
• Experiment with different price drop percentages (e.g., 5%, 10%, 15%) and trigger windows to find the sweet spot where urgency meets conversion without over-discounting

Results:

• 49X ROI from Insider-driven campaigns
• 54% increase in conversion rate from the price-sensitive segment
• 12.1% uplift in click-through rate versus non-targeted campaigns
• 7.2% overall boost in marketing ROI

Architect helped us build a truly omnichannel marketing experience for our customers, enabling us to engage them on the right channels and at the right time. The tools under Sirius AI not only enhanced our marketing performance but also significantly boosted our team’s productivity. This resulted in a 12.1% increase in average click-through rate, demonstrating how effectively our messaging resonates through advanced segmentation and predictive AI capabilities.

            — Ecommerce Director, Slazenger

Want to identify high-intent users and convert them with AI-powered incentives?

🚀 Explore Insider’s Sirius AI, the patent-pending generative engine powering personalized and high-converting experiences with ease.

Build a Better Email List with Insider

In 2025, effective email list growth strategies are a compounding advantage, if done right. 

A stronger email growth list means better data, smarter segmentation, and higher retention over time. But marketers are well aware of how scale doesn’t come from pop-ups and batch sends. 

The brands winning today don’t rely on generic tactics. Instead, they use AI email marketing, real-time triggers, value-based capture, and omnichannel engagement solutions to turn intent into organic engagement. Ready to grow your email list with personalization and performance built in?
Book a demo with Insider today!

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