When List Growth Stalls, the Problem Is Usually on the Brand's Own Site

Growing email and SMS lists is marketers' second-biggest challenge in 2026, behind only conversion rate, according to Attentive's Marketer Pulse. (The CMO Wire is powered by Attentive.) Many brands have cut paid media and are seeing less site traffic as a result. But Attentive's list growth research, which surveyed 600 US consumers in April, points to causes brands can fix without new traffic. Seventy-two percent of shoppers say pop-ups usually appear before they're ready to sign up, and 70% say they often see sign-up offers from brands they already subscribe to.

Why is list growth harder this year?

Several pressures arrived at once. Brands pulling back on paid media are getting less site traffic. Shoppers are more selective about which brands they buy from and which they let into their inbox. Reaching those who do subscribe has become more complicated, too. With Apple's iOS 26, users who enable unknown-sender filtering may have texts from unfamiliar numbers routed to a separate inbox, making it easier for new SMS subscribers to miss messages they've signed up to receive.

Attentive's research suggests the first place to look is the sign-up experience itself. It recommends treating sign-up unit impressions as an early warning: if impressions drop while traffic holds steady, a display rule, disabled unit or broken integration is the likely cause.

What should brands check first?

The units they already have. Pop-ups get switched off during site updates, welcome codes expire and old display rules keep units hidden from most visitors. None of these show up in a traffic report.

Brian Campbell, founder and CEO of CrucialPoint, told CMO Wire that his free account audits regularly find sign-up forms that have stopped passing data and subscribers who never enter their flows. His method is narrow and fast. "Set a timer on your phone. Just spend 30 minutes and try to find as much as you can," he said.

Attentive suggests subscribing through every unit on a fresh browser, on desktop and mobile separately, and confirming that the welcome message arrives and the offer code works at checkout.

Which sign-up incentive works best?

A discount, in most cases. Eighty-nine percent of email subscribers and 85% of SMS subscribers in Attentive's survey said a welcome incentive influenced their decision, and close to half won't sign up without one. Attentive's platform data shows sign-up units with a discount bring in roughly 55% more subscribers than a generic "stay in the know" prompt.

The company recommends testing discount levels in 5% steps, going no lower than 10%, and offering a slightly larger incentive for SMS. Eighty-three percent of shoppers said they're more likely to join both email and SMS if they get better perks for doing so. Shoppers also want to know what they'll get after the welcome offer: 81% are more likely to sign up for both channels when the benefits of each are clear.

When should the pop-up appear?

Later than most brands show it. Seventy-two percent of shoppers said pop-ups usually appear before they're ready, and 66% said they're annoyed when one appears before they've had a chance to look around. Attentive recommends testing triggers such as scroll depth, time on page, exit intent and add-to-cart, and keeping a small persistent bubble on the site for shoppers who closed the first prompt.

Kuki Vincent-Osei, CEO of Republik Marketing, told CMO Wire that the pop-up is also where personalization begins. "It starts at the pop-up. Try to qualify them before you even get their email address, and ask them a couple questions," she said. Attentive's survey found 75% of shoppers are open to answering a few quick questions at sign-up if it makes the marketing more relevant.

Recognition matters as well. Seventy percent of shoppers said they often see sign-up offers from brands they already subscribe to, a sign the brand can't tell who its subscribers are when they return. CMO Wire's earlier reporting on first-party data covers the identity work that fixes this.

What does iOS 26 change for SMS sign-ups?

iOS 26 sends texts from senders a user doesn't recognize to a separate inbox with notifications silenced. Subscribers who opt in through desktop forms or some third-party pop-ups may never see a brand's messages, even though they asked for them.

Attentive recommends having subscribers start the conversation from their phone. On mobile, that means a sign-up flow where the shopper sends the first text. On desktop, it means a QR code that lets shoppers complete the opt-in on their phone. Text-to-join keywords also work. For subscribers who joined another way, Apple says filtering no longer applies after three replies to a sender's messages, making conversational texts that encourage responses potentially useful.

How do brands stay compliant while growing?

By building consent into every unit. SMS opt-ins carry real legal exposure. CMO Wire has reported that about a dozen states now have their own TCPA laws, so a single text campaign from a national brand can fall under several at once. The FCC's delay of its "revoke-all" rule to 2027 hasn't slowed state legislatures or the courts, as CMO Wire's coverage of brands rebuilding consent explains.

For email, the same consent discipline protects deliverability. Attentive's guide to improving email deliverability recommends double opt-in as a way to keep invalid and unwilling addresses off the list from the start.

How do brands keep the subscribers they earn?

Half of email subscribers and half of SMS subscribers in Attentive's survey said they had recently unsubscribed soon after signing up. The most common reasons were too many messages and having joined only for the welcome offer.

Campbell argues brands give up on non-buyers too early. He recommends carrying offers past the first week and into broadcast and abandonment messages. "These are always seen as retention channels, but they can also be used as acquisition channels," he said. Among shoppers who stayed subscribed after a first purchase, loyalty updates (68%) and offers that felt worth it (65%) were the top reasons.

FAQ

Why did my email and SMS list growth slow down? Check sign-up unit impressions first. If impressions fell while traffic held steady, a display rule, disabled unit or broken integration is the likely cause. If shoppers see the units but don't subscribe, revisit the offer, timing and design. If traffic itself fell, add touchpoints that don't depend on it, such as QR codes in stores and packages.

How does iOS 26 affect SMS marketing? iOS 26 filters texts from unrecognized senders into a separate, silenced inbox. Subscribers who joined through desktop forms or some third-party pop-ups may never see a brand's texts. Sign-up flows where the shopper sends the first text, desktop QR codes and text-to-join keywords avoid the problem.

What sign-up discount should brands offer? Attentive recommends testing in 5% steps and going no lower than 10%. Many brands offer a slightly larger incentive for SMS, since shoppers subscribed to both email and SMS tend to be more loyal.

When should a sign-up pop-up appear? After the shopper has shown some interest, such as a few seconds on the page, some scrolling, or an exit or add-to-cart action. Seventy-two percent of shoppers say pop-ups usually appear before they're ready.

Why do new subscribers unsubscribe so quickly? The most common reasons are too many messages and having signed up only for the welcome offer. Clear benefits beyond the first discount, a post-purchase series and loyalty updates give subscribers a reason to stay.