Have you ever noticed how an online search for running shoes seems to follow you across the internet? One minute you are browsing for sneakers, and the next, every website and app is showing you the same or similar products. This is personalised advertising – the modern marketer’s favourite tool, powered by data, algorithms, and artificial intelligence. The logic is simple: if an ad matches your interests, you are more likely to buy. But does it really work? Or could it sometimes do more harm than good?
A new study by Dominic Yeo, Hang Chu and Qiqi Li (2025) sheds light on this question by combining the results of dozens of smaller studies involving thousands of consumers. Their findings show that personalised advertising can indeed be persuasive, but not always, and not for everyone. It can strengthen engagement and even increase sales, but it can also make people uncomfortable when it feels too personal or intrusive. In other words, personalisation can attract or repel depending on how it is used.
The research found that personalisation works best when it is relevant but not invasive. Ads that reflect people’s general interests, such as recommending items like what they have bought before, usually perform well. But ads that reveal too much knowledge of a person’s private browsing habits or location tend to make people uneasy. Consumers like to be understood, but they do not want to be watched. As the authors put it, “the line between personalisation and privacy violation is very thin.”
Interestingly, the effectiveness of personalisation also depends on what is being sold. For products that are fun, emotional, or self-expressive, like clothing, music, or restaurants, personalised messages work very well because they tap into people’s feelings and identity. But for serious or functional products such as banking, healthcare, or insurance, personalisation is less effective. When consumers are making rational, high-stakes decisions, they tend to value accuracy, transparency, and fairness over emotional appeal. The study therefore challenges the belief that “more personalisation is always better.” It shows that persuasion depends as much on context and trust as on technology.
Another factor is how people perceive the company behind the message. When consumers believe a brand uses their data responsibly, they are more likely to respond positively to personalised content. But when they suspect misuse, even the most relevant ad can provoke irritation or distrust. This reinforces an important truth for today’s digital marketers: personalisation is not just about technology – it is about relationships. People are willing to share their data when they feel respected. When that respect is missing, technology cannot save the message.
A familiar example is how digital platforms in Nigeria now serve hyper-targeted ads for everything from bank loans to online betting. A professional who once searched for “SME funding” on Google may soon see loan ads from several Nigerian banks across Instagram and news websites. Initially, this feels helpful until the ads keep following them long after they’ve secured a loan or start showing up on family devices. At that point, what began as relevance starts to feel like surveillance. Nigerian consumers, who are increasingly tech-savvy but also privacy-conscious, often describe this experience as “too much”, illustrating exactly what this study found: personalisation works only when it feels respectful, not invasive.
For marketing professionals and business leaders, the implications are practical. Personalisation should be applied strategically, not automatically. It works best for lifestyle and emotional products where relevance drives interest, but it should be used carefully for sensitive or serious offerings. Transparency is essential; brands that explain why someone is seeing an ad build trust. Companies should also empower customers to control their data, allowing them to opt in or out easily. This not only reduces resistance but can also improve engagement, because people feel they are choosing the interaction. Above all, marketers should measure long-term trust, not just short-term clicks. A campaign that lifts sales today but erodes credibility tomorrow is no success at all.
Looking ahead, artificial intelligence will make personalisation even more powerful—and more delicate. Algorithms are now capable of predicting not just what you like, but when and how you might be most likely to respond. Ads can adjust in real time to your mood, location, and even facial expression. But with this power comes risk. The more precisely an ad targets a person, the easier it is to cross the line into manipulation. The brands that win in this new landscape will be those that balance relevance with respect and use technology to serve people rather than exploit them.
Personalised advertising is, at its core, a question of ethics as much as efficiency. When done thoughtfully, it makes customers feel understood and valued. When overdone, it invades their space and damages trust. As this study reminds us, persuasion in the digital age is not about how smart our algorithms are – it’s about how “human” our marketing remains.
Omagbitse Barrow is the Chief Executive of the Abuja-based strategy and management consulting firm, Learning Impact NG.
