"Really successful small businesses think about this all the time, how to create an emotional connection and how to create a feeling of personal connection ... the more large brands can think like that, the far more comfortable they'll be in a social [networking] space."
As Facebook's director of global creative solutions, it is the UK-based Kiwi's job to help some of the world's largest businesses take advantage of the social network, which at last count had one billion people using it each month.
Companies have been keen to get the attention of these consumers. According to United States media reports, Facebook's advertising growth was likely up 49 per cent in the fourth quarter of last year, on the back of a 36 per cent increase in the previous quarter.
Figures from this market have not been published but late last year a local ad executive estimated Facebook's total revenue from New Zealand would be "significantly more than $400,000".
So if New Zealand businesses are looking to boost their presence on Facebook, who should they emulate?
D'Arcy says Moa Beer's strategy during last year's Olympics, where the New Zealand team sponsor posted updates on the Kiwi athletes' performances, stands out for him.
"I thought they did a really good job (using) something they were authentically invested in," he said.
"Authenticity is the key thing. What are you genuinely passionate about? Because people can tell that and people who have that shared passion will connect."
Daily-deal voucher service GrabOne was another business using the social network effectively, he said.
Although his work at Facebook has brought D'Arcy in contact with Fortune 200 firms, the AUT graduate was no stranger to working with big brands. Since moving to New York at the age of 23 he had been involved with ad campaigns for firms such as Sony and Virgin Atlantic.
After stints at a number of ad agencies, D'Arcy spent seven years at Time Warner - the world's second largest media company - and was named president of one of its divisions in 2009 before joining Facebook about two years later.