South Africa, Jan. 19 -- "No longer do brands have to worry about one consumer telling another about bad service, but rather one disgruntled consumer telling hundreds of others through social media," says veteran marketer Chris Moerdyk about the new world of instant feedback between buyers.

But this nightmare scenario is just one side of the coin for retailers; the other is that good products, great service and a positive all-round experience are as easily and widely shared. And this 'word-of-mouth marketing' can be solid gold for sellers.

A 2020 study by UK market-research firm Kantar Media indicated that 93% of consumers trust the opinions of friends and family when purchasing products or services, while a recent report on American te...