Email marketing and SMS: direct channels with clear rules

Email marketing and SMS remain the two direct channels with the highest return, and they share the same requirement: a consented base and delivery that works. Email returns between 10 and 36 times the spend, according to Litmus, and automated messages outperform standard campaigns by a wide margin. The starting point is consent, not volume.

Two direct channels, one common requirement

Email and SMS reach a person, not an audience. That is why European rules treat them as direct commercial communications and require specific, documented consent, separate by channel and by purpose. Italy's data protection authority asks that users know which sectors they accept and through which channels, and treats generic wording as insufficient. For telemarketing, the Public Register of Objections adds a check that businesses must run before contacting a number.

The return on email

The ratio between revenue and investment places email among the most efficient channels: Litmus reports a return between 10:1 and 36:1 for most companies. Brevo's 2026 benchmark, built on data from more than 175,000 customers in 2025, measures an average open rate of 20.73%, rising to 33.87% when Apple-registered opens are included, and a click rate of 2.27%.

The most useful figure concerns automation. Messages triggered by behaviour reach 30.63% opens and 7.39% clicks, against the values of standard campaigns. The average unsubscribe rate is 0.46%, and in Europe the open rate rises to 22.83%. The operational conclusion is that list quality and message relevance matter, while increasing volume produces diminishing effects.

Delivery is a technical condition

An email that does not reach the inbox produces no result. Since 1 February 2024, Google asks all senders delivering to Gmail to set up SPF or DKIM authentication and to keep the spam report rate below 0.3%. Those sending more than 5,000 messages a day must add DMARC, align the sender domain with SPF or DKIM and offer one-click unsubscribe, with the `List-Unsubscribe` and `List-Unsubscribe-Post` headers.

These rules move delivery from the sending provider to domain configuration and sender reputation. An unclean list, incomplete authentication or a high spam rate reduce deliverability even when the content is sound.

SMS: immediacy and consent

SMS keeps an advantage: it reaches the personal device and is read quickly. The price of that immediacy is stricter consent. Opt-in must be explicit and channel-specific, and double opt-in is the evidentiary standard that proves consent exists and was not entered by someone else. Italy's data protection authority fines SMS campaigns without a valid basis, and the check covers both collection and how the proof is stored.

For a small business the consequence is practical: SMS works on a narrow, consented base, with short messages and a clear offer. Consented data collection is the foundation of the channel, and the end of contextual profiling makes direct contacts more valuable.

Measure and integrate

The two channels work better together and with the rest of the digital system. Consent management tools record when and how a person agreed to be contacted; segmentation decides who receives what; automation covers the moments when a message is expected, such as an order confirmation or a cart recovery.

Measurement follows three indicators: deliverability, meaning how many messages reach the inbox; engagement, with opens and clicks; and the result, with contacts and sales generated. A rising unsubscribe rate signals a problem of frequency or content, to be fixed before any other change.

A method for a small business

The first step is the database: where contacts come from, with what consent and with what proof. The second is delivery: domain authentication, reputation and regular list cleaning. The third is content and automation, built around the moments when the customer expects a message. Sending volume comes last.

On this basis direct channels become sustainable: an email or an SMS arrives, is read and leads to an action. The difference between a list that produces and one that consumes budget lies in the quality of consent and in the care given to delivery, not in the size of the database.