In my youth, it was a common sight to find men’s phone numbers scrawled into the walls of public toilets, often accompanied by indecent proposals. Many of these were probably written by lads pranking their straight friends, but a significant proportion must have been serious attempts to reach out to gay men in the area.

So what has that got to do with product-market fit? When I was growing up, there was no Grindr. This meant that gay men had to use a workaround to find partners. The existence of this inconvenient and uncomfortable workaround shows pent-up demand for a better way.

I see far too many startups who pitch me the Next Big Thing, without a real understanding of the value of the idea they’re proposing. The critical question for almost all businesses to answer is “who cares”. Sadly, the answer is all too often “nobody”. The proposition simply doesn’t attract users. It doesn’t solve anyone’s problem.

This can be hard for founders to accept. Often, they are so convinced by the obvious brilliance of their own creation, that they’re unable to comprehend the crashing indifference with which the market regards it.

How can founders detect real *need* for their product, before going to the effort of building it, then spending money on promotion? Here we return to the toilet wall: you look for the workaround.

Is there a clear sign that such a workaround is in general use in the market you’re trying to attack? Writing your number on a loo wall is hardly an appealing way to find a partner, so there’s clearly a big pain point to be solved. Latent demand for Grindr was high – an nobody needed to build it to prove this point.

Looking back at your own product, is there clear evidence that people are putting themselves to considerable trouble to solve the problem already? Is there a quantum leap in the quality of the experience they’ll get if they switch to your solution. If you can’t give a resounding “yes” to both questions, your market may soon overwhelm you with its total indifference to your magical, genius product.