It is within living memory that one of the most common ways of publicising a message was to wear a sandwich board with a suitable slogan painted on it, and to walk up and down the local high street.
For those of you who can't remember a time before the internet, a sandwich board consisted of two hinged sheets of heavy card or wood with a hole cut in the hinged edge. The wearer's head is placed through the hole and the two boards hang front and back. For a while, it was the height of fashion for any committed political radical, religious evangelist or village fete organiser.
But nowadays, if sandwich boards are remembered at all, it is often because of a phrase that now seems synonymous with the low-tech messaging device: 'The end of the world is nigh!'
There were other ways of phrasing the message, such as 'Armageddon approaches', 'The Apocalypse is coming', or even 'We're all doomed'. But the overall message was consistent: time to prepare for The End. And whilst sandwich boards may have gone the same way as the dinosaurs, the message that the world is about to come to a dramatic and calamitous conclusion retains a powerful presence online.
The justifications for this pessimistic outlook are many. Long-held views on religious doctrine and the 'inevitable' outcome of political conflict still come close to the top of the list. But the immediacy of such contemporary events as climate change, the outbreak of Ebola in West Africa last year, and the likelihood of comets or asteroids colliding with our planet have added to the clamour.
And whilst those who believe that the 'end of everything' is about to arrive may still be a minority, there is no doubt that the immediate availability of information about all the disasters, crises and emergencies that happen every day around the world encourage concern.
And it is those everyday catastrophes that are spurring more and more people to take measures that will help them overcome adversity. The stockpiling of food against the risk of flood or famine has been undertaken since the days of Noah. But the technological advances of the 20th and 21st Centuries have presented us with modern essentials that are likely to be disrupted in an emergency. Light, energy generation and storage, and communications are, in many parts of the world, reliant on large-scale infrastructures that are susceptible to the ravages of extreme weather events, civil unrest or military conflict.
Which is why growing numbers of people are putting together emergency preparedness kits which include not just tinned and dehydrated foods and medical supplies. Many are also packing solar powered and/or hand-cranked flashlights, radios and phone chargers, such as Freeplay's Tuf and Buddy products. These items help people caught up in a crisis to see what they are doing, listen to the latest news alerts and stay in touch with family and friends - even when the power goes down and disposable batteries are hard to come by.
So, next time you are on the receiving end of a power outage, reach for your emergency preparedness kit, plug your smartphone into your Freeplay charger, spark up your web browser and check to see if the end of the world really is nigh. It's a lot easier than trying to find a man wearing a sandwich board!