Customer Acquisition: Definition, Bedeutung & Beispiele im Direktmarketing

What is Customer Acquisition? -- Definition and Distinction

Customer acquisition encompasses all strategic and operational measures used by a company to convert individuals or businesses into first-time buyers who previously had no business relationship with the company. The central control metric is Customer Acquisition Cost (CAC): total marketing and sales costs divided by the number of new customers acquired in a defined period.

The distinction from related terms is important: Lead generation refers to identifying potential prospects -- it is the precursor to customer acquisition. Customer retention aims at repeat purchases and customer loyalty. Both disciplines complement each other but differ fundamentally in costs and methods. According to Harvard Business Review, customer acquisition is 5 to 25 times more expensive than retaining existing customers. At the same time, it is indispensable for every company: without new customers, the customer base shrinks through natural attrition.

In direct marketing, customer acquisition has special significance because direct mail offers a unique legal advantage here: while email marketing to new customers without explicit consent is prohibited (Section 7(2) No. 3 of the German Unfair Competition Act), direct mail to new customers is GDPR-compliant without opt-in (Art. 6(1)(f), legitimate interest). This makes the mailbox the only channel through which companies can directly and personally address potential new customers without first obtaining consent.

Customer Acquisition via Direct Mail: The CMC Data

The CMC Print Mailing Study 2021 provides the only published empirical data on customer acquisition via print mailing in German e-commerce. For the first time, the activation performance of mailings for new customers -- i.e., people without an existing customer relationship -- was systematically measured. The results show that direct mail is an economically attractive acquisition channel even beyond customer retention.

The average response rate for new customer mailings was 1.0 percent, with a peak value of 3.0 percent. While this may seem low compared to the 4-5 percent for existing customers, it is remarkable for cold prospecting: Google Ads achieve similar or lower conversion rates in many industries at significantly higher per-unit costs. The cost per order (CPO) averaged 40 EUR, with fully addressed mailings being more expensive at 46 EUR but also 22 percent more effective with a 1.2 percent response rate compared to partially addressed mailings (0.9 percent, 32 EUR CPO). The ROAS was 250 percent -- every euro invested in advertising generated 2.50 EUR in revenue from new customers.

For comparison: the CMC studies from 2022 to 2025 measure CVR values of 4.1 to 5.4 percent and ROAS values of 734 to 1,011 percent for existing customers. The difference is explained by the existing customer relationship -- existing customers know the brand, trust the sender, and have lower purchase barriers. Nevertheless, the CPO of 40 EUR for new customer mailings is competitive: according to industry benchmarks, the average cost per new customer for Google Ads in Germany is 25 to 45 EUR in e-commerce -- with an increasing trend. According to a Growth-onomics analysis, CAC has increased globally by around 60 percent over the past five years, driven by stronger competition and stricter data protection regulations.

Industry-Specific Strategies: Where Direct Mail Wins Customers

The particular advantage of direct mail lies in its local and industry-specific applicability. While digital channels are often optimized for broad target groups, a print mailing can be precisely tailored to a company's catchment area and target audience. Three industries stand out particularly in customer acquisition via mail.

Real estate agents have been using direct mail as their primary acquisition channel for decades -- known in the industry as "farming." An agent concentrates on a defined area and regularly sends personalized letters to homeowners. The method is particularly effective because real estate decisions are local in nature and a physical presence in the mailbox builds trust. With carefully segmented lists, real estate mailings can achieve significantly above-average response rates -- field reports cite values of 5 to 8 percent for personalized invitation cards sent to selected households.

Craftsmen and tradespeople benefit from the regional reach of direct mail. Flyers and brochures in the mailbox are among the most efficient acquisition methods for home services trades -- from roofers to painters to landscapers. The combination of partially addressed mailings (POSTAKTUELL) for distribution in the catchment area and fully addressed mailings (Dialogpost) for targeted follow-up campaigns offers good cost-effectiveness.

B2B service providers are increasingly relying on direct mail as part of account-based marketing (ABM). While cold emails in the B2B sector are often ignored, the physical sales letter to decision-makers achieves significantly higher attention. According to an analysis on our blog, B2B sales letters to decision-makers achieve response rates of up to 9 percent -- many times higher than cold email campaigns (typically 0.5-1 percent). Highly personalized follow-up mailings to C-level decision-makers as part of account-based marketing are particularly effective.

Legal Foundations: GDPR and Customer Acquisition

The greatest advantage of direct mail in customer acquisition is legal in nature. While digital channels are increasingly restricted by data protection regulations -- cookie consent, iOS tracking transparency, Digital Markets Act -- direct mail to new customers remains permissible without prior consent.

The legal basis is Art. 6(1)(f) GDPR (legitimate interest), supported by Recital 47, which expressly mentions direct marketing as a legitimate interest. The Stuttgart Regional Court confirmed on February 25, 2022, that addressed direct mail for customer acquisition is legally compliant under data protection law. In contrast, Section 7(2) No. 3 of the German Unfair Competition Act classifies email advertising without explicit prior consent as unreasonable harassment -- and cold calling to consumers (B2C) is fundamentally prohibited.

Several legal avenues exist for address procurement: List brokers and address publishers provide addresses based on legitimate interests or with advertising consent. Public registers (commercial register, business registrations) provide B2B addresses. Deutsche Post Direkt offers micro-geographic characteristics for lookalike modeling with its Microdialog database. And the lettershop procedure makes it possible to use third-party addresses without owning them -- the lettershop addresses and ships, the client never sees the addresses. Regardless of the procurement method: every new customer mailing must include a notice of the right to object according to Art. 21(2) GDPR.

Optimizing ROI: Success Factors for New Customer Mailings

The profitability of new customer mailings depends on three levers: target group selection, offer design, and timing. The CMC studies provide concrete benchmarks for this.

For target groups, RFM analysis (Recency, Frequency, Monetary Value) is the gold standard: the best existing customers are used as a reference for lookalike models. Deutsche Post Direkt enriches these profiles with over 100 micro-geographic characteristics and identifies statistically similar households in the market. The result: higher conversion rates and less waste than with untargeted distribution.

For offer design, the CMC studies show clear patterns: high voucher values achieve 61 percent higher CVR than low ones (CMC 2022). Percentage vouchers perform 23 percent better than fixed-value discounts (CMC 2022). And a separate voucher card as an insert increases CVR by up to 33 percent (CMC 2023). For new customer mailings, this means: a generous first-time buyer discount significantly lowers the barrier to the first purchase.

For timing, it should be noted that 51 percent of orders only come in from the fifth week after mailing dispatch (CMC 2022). The measurement period should therefore be at least 8 to 10 weeks. At the same time, the 2021 CMC study proves for existing customers that an email reminder after the print mailing doubles the conversion rate -- an effect that only works for new customer mailings if an email address is already available. The combination of print + digital maximizes return.