Ninety-five per cent of people respond negatively when an advertisement sent by email uses their name.
And computer users unfamiliar with the firm sending the email are highly likely to delete and unsubscribe from personalised messages, researchers claim.
Turn-off: Junk emails which greet people by name are far more likely to repel potential customers than endear them, according to a study
A study led by Professor Sunil Wattal, from Temple University Fox School of Business in Philadelphia, Pennsylvania, looked at ten million marketing emails sent from a real-world firm to 600,000 potential customers.
He found that consumers' responses to personalised greetings ranged from very negative to, at best, neutral.
Overall, 95 per cent of customers responded negatively when an email ad greeted them by name.
While people who were unfamiliar with the firm were highly likely to delete emails with personalized greetings, customers who were more familiar with the firm were less likely to do so.
But even these people still responded more negatively to personalised emails than those without greetings.
Customers who had made past purchases, on the other hand, were unaffected.
Past research into sales strategies has suggested consumers generally react positively to being recognised by name.
'Most consumers are wary of emails, particularly those with personal greetings'
But Professor Wattal suggests the variable introduced to online environments - the fear of privacy invasion - heavily outweighs the intended personal touch.
He said: 'Given the high level of cyber security concerns about phishing, identity theft, and credit card fraud, many consumers would be wary of e-mails, particularly those with personal greetings.
The researchers also found that product personalisation, in which customers are directed to products that their past purchasing patterns suggest they will like, triggered positive responses in 98 per cent of customers, with the positive effect being most pronounced among customers unfamiliar with the firm.
Since consumers may not have known these product-personalisation emails used their personal information, researchers suggest that no red flags about privacy were raised, and thus consumers only experienced the positive aspect of these email advertisements - exposure to desirable products.