But while the Coke ad, from 40-odd-years ago, was considered a masterpiece, the Pepsi ad has gone down with its audience like an especially ugly brick.

Pepsi was quick to pull the ad and issue an apology. “Pepsi was trying to project a global message of unity, peace and understanding,” it said, “clearly, we missed the mark and apologise. We did not intend to make light of any serious issue.”

Meanwhile, Nivea has been busy pulling one of its ads.

In the case of Nivea, it is very hard to see how the ad ever got approved: "Keep it clean, keep it bright. Don't let anything ruin it," ran the copy with the accompanying headline: "White is purity." The ad appeared on its Middle East Facebook page. Well, no excuses for that, the flaws in this ad should have been spotted on day one.

But what about the Pepsi debacle?

It is not usual for brands to link themselves to political causes: if their target audience holds a specific set of attitudes, then backing the campaigns this group feels an affinity to, can pay dividends. Ads from Airbnb and Google showed during the Super Bowl had an unmistakably pro-diversity anti-Trump theme.

Indeed, effective ads carry risks. And risks, by definition, can back-fire or else they wouldn't be risks.

And Pepsi got it wrong.

Nicola Kemp, trends editor at advertising trade magazine, Campaign, was quoted as saying that the problem may have been that Pepsi made the ad in-house, rather than employ the services of an agency.

Others say the company was just too late, jumping on a bandwagon rather than trying to help it gain momentum.

Frankly, the Pepsi ad didn't seem to be saying anything. In fact, it was unclear what the demonstrators were protesting about. It seemed more like a party. You could tell that the watching policeman were dying to join in.

Maybe, to run ads like this you just have to know what you are doing. You need expertise, you need better understanding of your demographic and the causes they support.

We are in the era when data analysis counts above creativity in the marketing process. But this may have a been an example of knowledge and understanding and a certain sympathy to the public mood counting for more than the ability to read data.

Pepsi’s big mistake may have been to invite its public to join a conversation which it hadn't even joined itself.