We’ve always known that word of mouth plays some part in purchase decision-making – we just did not know when it worked and when it didn’t.

As a medium of persuasion, word of mouth exerts most influence when buying clothes and food; you are less likely to be influenced verbally when it comes to alcoholic drinks and cars.

Media planners ought to take the cue here – go viral for clothing and food brands as this method tends to generate conversation and stick to more traditional advertising modes with other categories.