THERE was a programme on Channel 4 on Wednesday called Airbnb: Dream Or Nightmare? It was one of those over-heated and slightly tacky affairs that assumes no one will watch a documentary unless it is sexed up a bit.

Our experiences as hosts for the short-term accommodation site have been almost entirely good, and the bad has been on the niggly side. Certainly nothing that would make a documentary for Channel 4 (or a feature for the Guardian: I’ve tried). A re-enactment of the man who made my wife feel uneasy with his grumpy presence in the house – and his later disparaging ‘review’ of his breakfast ‘without the stated fruit juice’ – would not account for much.

This documentary tried to balance the good with the bad, but ended up piling on the negativity. Some of it was shocking, such as the properties trashed when parties were thrown by guests; some of it was shocking and perhaps surprising. Would you let out a beautiful new apartment in London to a group of strangers? Nope, me neither, but there you go. I don’t have one of those. Just a spare room.

A short interview with a happy host, and clips with grateful guests, were scattered amid the misery. There was valid criticism of the way Airbnb can unbalance housing stock, especially in cities such as London, and cause problems when tenants sub-let their flats without telling their landlords.

Footage in Los Angeles, the spiritual home of Airbnb, showed people invading the company’s headquarters in a protest about housing needs. A similar protest took place in New York, except that hosts turned up to as well to stick up for Airbnb.

What you have here is clash between modern idealism, as rapidly incubated on the internet, and good old greed and foolishness. The original idea for Airbnb is great: if you have a spare room, let it out to a visiting stranger; invite them into your house and then send them on their way with a happy wave.

That pretty much encapsulates our experience, although the pleasure to be had in hosting guests from around the world is balanced by the circumstances that make it necessary. We started doing this after I lost my job and there are nights when you wish you still had the house to yourself.

On the micro level in the Cole house, Airbnb is a good thing: it adds a little to the family coffers in lean times and most of the guests are lovely, and fully appreciate our house and their stay.

The bigger Airbnb has become, the more likely it is that someone will try and cash in by earning money from crappy rooms or turning the social sharing economy into a hard business hiding behind soft intentions.

Airbnb is worth untold billions, which is a mystery to me (my own wealth is also untold). But it’s still a minnow next to Facebook. Yesterday the site’s founder, Mark Zuckerberg and his wife, Priscilla Chan, announced they wanted to tackle all diseases and pledged $3bn to fund medical research with the ultimate goal being to “cure, prevent or manage all diseases by the end of the century”.

The reaction from the medical establishment has mixed praise with a degree of caution. Dr Sheena Cruickshank, lecturer in immunology at the University of Manchester, told the BBC that treating diseases was not a “static field” – “Everything changes. Our immune systems change, diseases often change.”

While she thought it was “brilliant” for the couple to invest in medical research, she warned that their aim wasn’t realistic, given the nature of disease and what we still have to learn.

Others point out that the sums involved, although generous, may well not be anywhere near enough. Others still – cynical others, perhaps – wonder if this isn’t one way for Facebook to stump up all the tax it has avoided paying.

Mostly we should wish them well with their philanthropy, even if it does come with the hard gleam of internet idealism.