In 2016, I used Airbnb to book a room in an apartment block in the Botafogo district of Rio de Janeiro.
It was a bit of a gamble: What if the neighbours were inveterate party animals or worse? Even more serious for a jobbing reporter, what if the Wi-Fi was less than 100 per cent reliable?
But it came up trumps. I spent an enjoyable Olympics in a pleasant district kitty-corner from a brilliant neighbourhood hang-out called Manolo's restaurant.
Equally important, my lodging bill for 16 days at a time of peak demand came to £740 ($955/€865), most of which went into the pocket of a bona fide local resident who, if I understood correctly, was a university librarian.
I hence avoided the rip-off prices - internal emails suggest that colleagues paid more than £5,000 ($6,450/€5,840) bed and breakfast for a somewhat longer stay - being charged for official Olympic media accommodation.
I am telling you this not out of smugness (OK, a little), or for posterity's sake, but in order to begin to explain something about the International Olympic Committee (IOC)/Airbnb worldwide sponsorship deal unveiled this week that immediately puzzled me.
The best sports sponsorship arrangements deliver substantial benefits for both parties - but of course.
With this one, you did not require a brain the size of Jupiter to spot the appeal for the IOC: $500 million (£386 million/€452 million), some of it in cash, and the addition of a buzzy new tech brand, not actually founded until the first week of the Beijing Olympics in 2008, to a roster of international partners which, though chock-full of solid corporate citizens, must still look a bit staid to denizens of that key youth demographic.
But why would Airbnb shell out a cool half a billion dollars, albeit partly in the form of its own product and over nine years, to forge a tie-up with a still potent, but distinctly ageing sports brand?
Looking for guidance from the press release, I read that the deal would give "community residents the opportunity to earn extra income by providing accommodation and local experiences to visiting fans, athletes and other members of the Olympic Movement".
"For visitors," the release went on, "the Airbnb community will offer a more local and authentic way to immerse themselves in the host cities and engage with the local communities.
"For the cities themselves, the Airbnb community represents a more environmentally sustainable way of accommodating a surge in visitors."
Yes, I got all that, but the thing bugging me was this: as my Rio experience demonstrated, Airbnb and its community of hosts has shown itself perfectly able to do all this without splurging its marketing budget on such a venture.
The company had, admittedly, signed up as an Official Supplier to Rio 2016.
But this is a comparatively modest level of commitment and, anyway, an email exchange with a Rio official from 2015 makes me wonder how much this was at Rio's, rather than Airbnb's, initiative.
"Due to the limited hotel inventory in Rio," this official wrote to me, "Rio 2016 recently signed a supplier agreement with Airbnb to try and further assist our official clients and public with their accommodation search."
Other possible rationales I have seen mentioned include:
1. The deal will help raise Airbnb's profile before a multi-billion-dollar public listing expected next year.
But this commitment runs all the way through until 2028, so I don't really buy that, certainly not as the sponsorship's fundamental motivation.
2. It is the corporate equivalent of a young banker splashing out on sports cars and luxury watches to show he has arrived.
It is an eye-catching line and there might be something in it, but, again, as a fundamental motivation for the deal?
My limited exposure to Airbnb, not to mention their growth record, suggest they are a wee bit cannier than that.
3. What about the Olympian Experiences aspect, whereby Airbnb customers will be able to purchase face-time with Olympic and Paralympic athletes, who will get paid for their trouble?
This is an interesting idea that dovetails well with an existing arm of Airbnb's business.
The IOC has just provided me with more information about how it should work that I will share on another occasion.
My hunch, though, is that this is a worthy, and potentially positive, add-on, and still not the, to me, elusive fundamental motivation for Airbnb’s hefty investment in the IOC.
Having discounted all of these for the reasons mentioned, I hit the business pages, and the penny finally dropped.
The narrative goes something like this.
Throughout the tech revolution of the past - what? - 20 years, the most successful new companies have been very good and efficient at matching supply with demand.
This is what grand-daddies of the sector like Amazon and eBay did to great effect with physical goods; and it is an approach relative newcomers such as Uber and Airbnb have sought to apply to specific services.
For some years now, their success has made them the darlings of entrepreneurs, and the cost-savings they have enabled have made them popular with the tech-savvy young professionals whose lifestyles they have facilitated.
But change generally creates losers, too, and in this case the losers are the established - regulated - sectors whose markets the tech gang are muscling in on; people like taxi-drivers and hoteliers.
These established interest groups have now started fighting back, as we have seen instantly in the way French hoteliers expressed their displeasure at the deal.
Some suspect this backlash by traditional trades, which are a source of tax revenue and hence tend to be politically well-connected, is only just beginning.
Janan Ganesh, an always shrewd, sometimes brilliant Financial Times columnist, last month lamented the possible demise of what he called the "middle-class world citizen".
One of the elements he speculated might contribute to this was the following: "The froideur between Airbnb and tourist cities escalates until the firm is garrotted in red tape."
That imagined dénouement is by no means imminent and, indeed, not remotely inevitable.
But battle has all too obviously been joined.
So, what might the fundamental motivation for this showy new IOC deal be from Airbnb's perspective?
Well, maybe the room-renting platform has realised, like other tech companies, that the extended honeymoon is over; that legitimate concerns over the wider social impact of its activities look increasingly likely to impinge in a material way on its business; and that it could therefore use some politically well-connected new allies, preferably on an international scale.
Seen in that light, the notion of getting into bed with the IOC, albeit at not insignificant cost, might begin to look like a worthwhile option.
The problem for the IOC, as we are already observing, is that the tie-up might pitch them involuntarily into one of the defining social tussles of the coming decade at a time when it already has more than enough on its plate.
This all promises to be as riveting as any gold-medal event.