Well the first thing, I got me a fuel pump
— Johnny Cash, One Piece At A Time
Above is an icon of a petrol pump, which you will see on pretty much every car dashboard. Most (not all) modern-ish cars also have a little triangle next to the petrol pump icon. That little triangle points either right or left: it is showing on which side of the car the hole for putting petrol in is. So the one above (with the triangle arrow thing helpfully coloured in red) means that the fuel pipe is on the left-hand-side of the car.
I did not know this. It turns out that lots and lots of other people do not know this either. The world seems to be divided into three roughly equal-sized classes: people who already know this and are amazed that everyone did not; people who did not know this and are amazed; and people who say “my car doesn’t have that, is it a US/UK/EU-only thing?”
There is a lesson here, though. This is, once you know what it means, quite an elegant little solution. Now that you know it, you’ll never pull into a petrol station on the wrong side of the pump ever again. It’s clever, it’s simple, and… half the people in the world don’t know about it. There are, I’m sure, conclusions to be drawn about usability studies, iconography, and so on. I mean, spare a thought for the usability testing team on your project at this moment. How do you test this? If you show someone the icon and say “what does this mean?” most people would (probably) guess correctly. The point here is: once you know that the triangle means something, it’s reasonably easy to guess what the something is. But if you don’t know that it’s there for a reason, a goodly proportion of people (myself included) will never think to wonder about it, and so won’t ever learn that it represents a useful bit of information. This has ramifications for how you yourself do usability testing for the things you make.
This has been a party political broadcast on behalf of the “semiotics is useless if you don’t realise there’s a meaning there to discuss, Umberto Eco” party.