It was one of those days. I was bored and on the internet. And without paying much attention, I clicked on a sidebar to see what the advert was about. A small act. But it would lead, over the subsequent year, to 68 total strangers arriving at my door, planning to stay the night. In that idle moment, I had signed up to be a host in one of the most successful travel start-ups of all time.

Airbnb was still in its infancy. It had been born, again by accident, two years earlier in 2007, when America’s Industrial Design Society held its annual conference in San Francisco and the hotels were chock-a-block. Two cash-strapped friends offered to put people up in their loft for a small fee. The response was so positive that they realised they had stumbled on something.

The idea of staying in real homes, and with like-minded people, was bankable. There was a hunger for something more real and rooted – not the anonymity of hotel chains, minibars and uniform foyers. And Airbnb founders Brian Chesky, Nathan Blecharczyk and Joe Gebbia believed that supply would match demand. There must, they reasoned, be other people with a bit of space they’d like to let and an outlook that would regard visitors as half guests, half lodgers.

They were stunningly right. When I became one of their hosts, although Airbnb was still operating from its founders’ loft, it had already gone international. Today the website lists apartments, rooms, houses and even tents and boats – from the humble to the palatial – in 186 countries and 16,000 cities. The company’s fortunes have burgeoned: last July, it raised $112m of funding and was valued at $1bn. But the site stresses that it is providing more than just a place to lay your head. It holds out a warm invitation – connect with locals, experience life as the natives alone know it, get under the skin of the city and be no longer a mere tourist. Airbnb speaks the language of community. It aspires to put the local into the global.

I knew none of this when I clicked on the link. Nor did any of my acquaintances. On the contrary, my kids thought I was mad and my ex predicted axe murderers and kleptomaniacs. My friends were aghast at the idea of giving a key to people who’d come without any testimonial or guarantee. Indeed, if I had known last summer’s horror story– when Airbnb guests totally trashed a house in Oakland, California, stealing passports and credit cards – I would have gone no further. But that was all in the future.

I was relaxed about it all at first. I offered a first-floor room in my Victorian terraced house in trendy Shoreditch, east London, and it was only when the first request came up on my screen that I began to realise what I had done. Two women from Chicago emailed to book a stay. I began to look at my house through strangers’ eyes, especially those of Americans – doubtless super-clean to the point of obsession. Would they turn their noses up at my mess of books and pictures? Would they run their fingers along shelves and inspect the backs of the toilets? For days, I sweated, hoovered, washed and wiped. I bought new mugs and better bedding. I even re-grouted the shower. Finally, I awaited Elizabeth and Kerry’s ring at the doorbell as if I was about to take an exam.

It was not as I had expected. On the doorstep stood a tall youth with the sweet face of a Botticelli angel and a skateboard under one arm. Half hidden behind him, beneath a gargantuan backpack, was a young dark-haired woman. He held out a spare hand – “Kerry …” I was speechless.

If you learn anything from Airbnb, it is to expect the unexpected. Of the regular stream of visitors, hardly any was as I had imagined. The Armenian sexologist was a retiring and graceful woman. The Turkish IT expert was a small moustachioed bundle of anxious energy who kept losing his keys. The marine who had served in Afghanistan was a slight bespectacled character, on an exotic world trip with his girlfriend.

The system couldn’t be simpler. The traveller searches the site to see what’s on offer in their city of choice, selects one that fits their taste and budget, and emails the host, who can then either accept or refuse. It was over-simple in the early days. Though guests do get reviewed by hosts (and the other way round), first-timers – and most of them were that – come with no form. I accepted people blindly, and quickly became almost blase. But the trauma of Oakland and the trashed flat proved a wake-up call for Airbnb’s easy-going young co-founders, who used to say: “Working for Airbnb is like a really fun school where you get paid.”

Grown-up couchsurfing needs some safeguards. Guests now need to include their personal details, hosts are asked to check that phone numbers are genuine, and a $50,000 policy has been put in place in case of further disasters.

All irrelevant for me with Kerry and Elizabeth – two charming vegans and ex-art students – and for the visitors who followed once my site had reviews. They brought bewildering questions and intentions. How could they get to CH Spurgeon’s Temple? It was top of the list for a couple from New York who could hardly credit that I hadn’t heard of it – nor of the pets’ graveyard in Hyde Park. And I didn’t know where the nephew of the founder of the Baha’i faith is buried (Barnet). I realised my knowledge of my city was patchy. People came with distinct Londons in their minds and I began to see it with different eyes.

Watching them from the sidelines is awe-inspiring. I am amazed by their energy, their zest. They walk incessantly. They are immensely curious about my life and my area – I am, I realise, part of their adventure – and sometimes it feels like speed dating. And on their side, they tell me about things I would never have known – the life of Russians in Lithuania, the art scene in Slovenia, voter registration campaigns in New York. And they try anything. They do things I had never thought possible. I’d politely poured cold water on one couple’s desire to get in to hear a debate in the House of Commons. No, they said, they had just walked in. And they bring with them scores of personal stories – so many that I am gutted not to know how they turn out. I am living in the middle of a flow of tales and am constantly having the denouements snatched away.

Here’s Frank with his girlfriend, who’d waited patiently for him while he served his time in Kabul. How have they settled down back home in the US? Will they stay together? Here is Tomas from Lithuania with his visionary plans for a sports start-up to which he has dedicated more than a year of his life plus his mortgage. Is it working? I find I really care. And Michael and Anna – a middle-aged couple who unselfconsciously hold hands as they talk. I ask how long they have been together.

“It’s very recent,” she says softly.

“And after a lot of pain for each of us …” he adds, and they look at each other tenderly, with a sense of quiet amazement at their good fortune.

Of course there is a downside. I am tired of laundering, ironing, cleaning. I find some people more interesting than others and have sometimes strained to share enthusiasms (Churchill’s bunker – hot favourite.) I don’t like it when people leave their plates for me to wash up and – once – their condoms to junk. There are times in between when I relish the silence, the ability to wander around if I care to in a state of undress. And there are times when the growth of Airbnb makes me feel my homespun offer is out of place among the holiday lets that are entering the fray. Am I, I wonder, being naive?

But then the riots happened, and in came emails – from ex-Airbnb-ers in Slovenia, Australia, America and Germany – inquiring if I am OK. It’s a reminder and an affirmation. There are people out there who want to find corner shops rather than faceless chains, fresh experiences rather than beaten tracks, and real people rather than robots. And that is worth all the laundry in the world.

Naseem Khan (airbnb.com/rooms/ 45087) charges from £55 a night for a double room, minimum three-night stay