Happy birthday Just Do It. Will Nike's famous slogan keep doing it for another 25 years?

But if this were to be a question on the TV game show Pointless, contestants would steer away from identifying Nike with ‘Just Do It’. It’s just too obvious.

‘Just Do It’, which celebrates 25 years of existence this month, is now part of the common vernacular, as entwined with the Nike brand as its swoosh, as indelibly linked to Nike as Michael Jordan and Phil Knight.

Visit Nike’s flagship store on Oxford Street and there are floor-to-ceiling piles of ‘Just Do It’ t-shirts, rivaling those of the Nike brand itself.

For a strapline to still be impactful after a quarter of a century is no small feat, particularly as we live in a data-driven fragmented media society which is at odds with the notion of a big campaign message like ‘Just Do It’.

Big campaign messages were the preserve of the 20th century, like Pepsi’s ‘New Generation’ and KFC’s ‘Finger Lickin Good’.

Now marketers tremble at the thought of an all-encompassing brand campaign which bestrides all social and demographic lines. It is simply too risky.

But this is what Wieden & Kennedy’s Dan Wieden created with ‘Just Do It’- a short, snappy phrase which has grown into the philosophical wrapper for the Nike brand.

Experts believe the key to its success is its vagueness: it can be applied to anything and it is much bigger than sport.

When the ads first aired, they marked a change in strategy from Nike, shifting away from its reliance on rebellious sports stars such as John McEnroe and Andre Agassi and elevating it from being a sports brand into a global fashion brand.

In a way, its durability is perhaps unsurprising as Nike has always been first out of the blocks when it comes to innovative advertising.

If one thinks about the word ‘content’, which is the word de jour and banded around nowadays to describe all forms of advertising… well, Nike was doing ‘content’ 25 years ago, when it sailed against the prevailing 30 second TV ads by doing its own thing and creating short films.

So will ‘Just Do It’ last another 25 years? Probably.

The only way it can become unstuck, according to one expert, is if it becomes shorthand for underperformance.

Andy Sutherden, global head of sports marketing and sponsorship at Hill & Knowlton, says: “One sure-fire way of reducing the shelf life of ‘Just Do It’ is to imagine the misfortune of Nike sponsored athletes or events continuously getting caught up in stories that bring unwanted headlines and associations for the brand. This is not exclusive to Nike - or indeed any brand with such a famous and distinctive way of describing itself.”

So too many of these could raise questions about its future. “Just Do It” was also on the ad Nike pulled showing Oscar Pistorius starting to sprint in his blades with the caption “I am the bullet in the chamber”.

To date, Nike has always dropped or suspended the athletes concerned, and maintained the strapline.

Yet in this era of unprecedented media scrutiny, “Just Do It” could become synonymous for something ugly and force Nike to drop it.

That said, Nike has hitherto rode out the controversies, from Tiger Woods’ sex scandal to claims that Nike’s factories are run like sweatshops, and it’s still as resonant today as it was in that first ad staring 80-year-old Walt Stack 25 years ago.

The straplines were for Reebok, Ellesse, Nike, Adidas, Lacoste, Umbro and Puma.

John Reynolds is a journalist who writes about media, marketing, sport, advertising and business