Great! I propose a concise 1-sentence summary that gets to the core of one of the main drawbacks of QF, and link to Mutual Matching, a 'decentralized donor matching on steroids', overcoming some of QF issues, that might have been interesting for the reader of this article.

QF really is an information eliciting mechanism, but much less a mechanism for solving the (obviously!) most notorious problem with public goods: the lack of funding due to free-riding and lacking incentives to contribute.

Yes, QF elicits the WTP, helping to inform about value & optimal size of the public good (PG). Is that what prevented us from solving the PG issues? Nope. It’s our lack of the central funder. As shown here, this funder would require deep pockets - sponsoring nearly 100% of the cost when $n$ grows large (!), see the $n^{2}x$ vs. $nx$ in the text. Lacking that funder, people again have insufficient incentive to contribute.

Mutual Matching, fully 'decentralized donor matching on steroids': With it, I address some core issues with QF. Donors mutually co-incentivize each other to donate more, by hard, direct incentives mutually created purely by their own conditional donations.

Arbitrarily high matching factor (->incentive) are theoretically achievable - well, in practice all depends on statistical distribution of contributors etc. It is the first attempt I’m aware of that most directly tries to scale up the simple idea of incentivizing with “if you give, I give” -> to $n$ people, each one with each one, without requirement to negotiate.

Thanks for the post, resonates a lot with my personal experience.

Couldn't agree more with

In my impression, the most influential argument of the camp against the initiative was that factory farming just doesn't exist in Switzerland.^[2] Even if it was only one of but not the most influential argument, I think this speaks volumes about both the (current) debate culture

In a similar direction, there's more that struck me as rather discouraging in terms of intelligent public debate:

In addition to this lie you pointed to apparently being popular*, from my experience in discussions about the initiative, the population also showed a basic inability to follow most basic logical principles:

1. Even many of the kindest people who would not want to harm animals, believed, as a sort of fundamental principle, it'd be bad to prescribe what animals people can and cannot eat, thinking that, therefore, it is fundamentally not okay to impose (such) animal welfare protection measures.
2. All while no single person (there will be the odd exception; but it really is an exception) would have claimed that the existing animal welfare laws would be unwarranted/should be abolished/relaxed.

Fair point, even if my personal feeling is that it would be the same even without the killing (even if indeed the killing itself indeed would alone suffice too).

We can amend the RC2 attempt to avoid the killing : Start with the world with the seeds for huge numbers of lives worth-living-even-if-barely-so, and propose to destroy that world, for the sake of creating a world for very few really rich and happy! (Obviously with the nuance that it is the rich few whose net happiness is slightly larger than the sum of the others).

My gut feeling does not change about this RC2 still feeling repugnant to many, though I admit I'm less sure and might also be biased now, as in not wanting to feel different, oops.

Might simply also a big portion of status-quo bias and/or omission bias (here both with similar effect) - be at play, helping to explain the typical classification of the conclusion as repugnant?

I think this might be the case when I ask myself  whether many people who classify the conclusion as repugnant, would not also have classified as just as repugnant the 'opposite' conclusion, if instead they had been offered the same experiment 'the other way round':

Start with a world counting huge numbers of lives worth-living-even-if-barely-so, and propose to destroy them all, for the sake of making very few really rich and happy! (Obviously with the nuance that it is the rich few whose net happiness is slightly larger than the sum of the others). It is just a gut feeling, but I'd guess this would evoke similar types of feelings of repugnance very often (maybe even more so than in the original RC experiment?)! A sort of Repugnant Conclusion 2.

Interesting suggestion! It sounds plausible that "barely worth living" might intuitively be mistaken as something more akin to 'so bad, they'd almost want to kill themselves, i.e. might well have even net negative lives' (which I think would be a poignant way to say what you write).

What about this to reduce the pbly often overwhelming stigma attached to showcasing one's own donations?!

1. Maybe the main issue is that I'm showing off with the amount I donate, rather than towards which causes. So: Just show where to, or maybe which share to where I donate, avoiding to show the absolute amount of donations.
2. Ok, so you do your donations, I do some other donations. But: You showcase my donations, I showcase yours. No clue whether that's stupid and not much better than simply not showing any personal donations. Maybe then, a bunch of us are donating to whatever each of us likes, but each of us simply showcases  the group's aggregate donations: "Hey, I'm in this group of five and it donated these amounts to here and here; I gave only a small share, but you could participate in sth similar".

Research vegan cat food as ideal EA cause!? Might also be ideal for human vegan future as 'side'-effect too.

1. Cats are obligate carnivores; must eat meat (or animal products) according to typical recommendations (and cats tend to refuse most non-animal foods). At least, there seems to exist no vegan cat food that is recommended as a main diet for cats without further warnings; often cats would seem to not accept mostly non-animal foods
2. I guess - but am not sure (?) - animals fed to cats mean significantly more animals are grown in factory farms
   1. Somewhat counterintuitively, in the whole cat food domain, the concept of animal welfare standards, does not even seem to exist. You can find some seemingly higher-welfare standard products but they are extremely rare
   2. Even if often large shares of the ingredients are "chicken meal", "fish meal" etc., I guess lots of this meal one way or another still could have been replacing some human foods in some places. What I have definitely seen, often major shares of ingredients in the cat foods are "meat" and not just inner organs or broth (although I cannot exclude that 'meal'-based ones may dominate total sales volumes)
   3. I guess we're pretty good feed all sorts of animal pieces to (i) ourselves in sausages, chicken nuggets, and the like and/or (ii) other food industry animals. So my prior is that cats do not only get stuff that is completely redundant in the food industry.
3. I calculate* (very rough) for ca. 220 mio. house cats worldwide, and considering 50% of their meat food to correspond to extra meat production, 6 600 ton/day quality-adjusted meat consumption, or around 0.9% of human's meat consumption.
4. The few articles I read online about to which degree cats require a meat diet, point mainly to elements that sound like those that we can easily mix/synthesise from non-animal foods and chemical processes (Taurine, Vitamins A, Arginine, Niacin, maybe some other fatty/amino-acids)
   1. Oddly, the pages tend to list these few elements, insisting that therefore the cat must eat meat, while I'd think: "Euhm, if it's just that, it would seem simple to mix the right thing" => maybe the pages just do not enter into more subtle details that are crucial for an obligate carnivore
5. IMHO, we could very easily test out food/supplements mixtures to check how easily one can replace which share of meat for cats without impairing their health. Given the billions of factory animal lives at stake, even some risk for the corresponding "test animals" might be completely justifiable in the worst case, and naive me thinks we might make extremely quick progress on this front if we really want
6. If we nail this, the positive side-effects could be: "Hey look, they even feed the obligate carnivores with this mix nowadays, surely you can also become vegan with zero hesitation with a human adjusted formula!" - i.e. finally the stories of your vegan friend who end up at the doctor who recommends him to eat meat (!) etc. could finally really be stories only of the past. (I know many think it already is; maybe you're right; but I know in practice at least for many this is simply not how they see it)
7. In fact, for each of (i) the cat-not-eating animals, and (ii) side-effect for human diet, I'd not be surprised if expediently trying to get vegan food that even cats can eat, would be justified

EA dietitians, am I just naive or could this be a thing?

I reckon one drawback of an ideal vegan cat diet could be that many more might want to keep cats. I see some possibilities on net impact from cats+food directly then:

1. Only few more cats: lower net animal consumption and lower net land-use and lower food costs for poor people (and for cat holders)
2. Much more cats: vegan diet more than offsetting the spared animal food industry footprint, i.e. larger net land-use change for agriculture, higher food prices for poor

Whether house cats are at all net "happy" or not, I do not know.

* Calculation, based on rough values:
220 mio domestic cats (ignoring 480 mio stray)
3 kg avg. weight (might be slightly low side)
2% of cat weight meat food/day
=60g/cat daily meat = 30g/cat daily "extra" animal meat if quality-adjusting with 50% (see text above)
=6 600 t/day extra meat production

And with approx. 90g meat/day per human (beef veal pork poultry and sheep acc. to OECD) for the 8 bn humans, i.e. with 750 000 t meat/day human consumption, the cat's share is

= 0.9%, bit simplistically approximated.

Great question!

1. Achieving a direct matching by the gvmt (even if it would be only with, say, a +25% match-factor or so, to keep it roughly in line with what tax-deductability means), instead of tax deductability, could indeed be more just, removing the bias you mention that unnecessarily favors the rich. Spot on imho.
2. That said, democracies seem to love "tax deductability": stealing from the state that feels a bit less like stealing. So, deductability can be the single mostly easily acceptable policy. If so, it might pragmatically be worthwhile to support it, despite the negative redistributional consequence just mentioned.
3. The best action might be to try to set up local EA charities that can easily get certified for tax deductability in Belgium, and use the money either directly to support the intl EA organizations, or, if that is difficult, then in the worst case simply to support similar work in parallel (?).
4. Mostly independently of 1. vs. 2., whether the (donation elasticity-adjusted) average donation is more effective than gvmt tax collection (or reducing standard gvmt tax burden*), feels difficult to say, and will depend a lot on how much you value different types of social goods. Atm, most donations will not be EA type donations, but one might expect people to give to causes often significantly better than for tax revenues, so I'd personally rather err towards the pro-deduct (or pro-match) side so far.

*It would be wrong to consider only 'tax revenue lost' for the gvmt as effect of the tax deductability. In expectation, in a simple model, gvmt will in the medium term partly respond with (i) lower expenditures, and (ii) increase standard tax rates in response to higher tax deductions. 

Btw, I personally would not worry about the €25 threshold. Avoiding to register/count too small sums seems a reasonable thing, even if you're right that it becomes less relevant in the digital world.

From what I read, Snowdrift is not quite "doing this", at least not in as far as the main aim here in Mutual Matching is to ask more from a participant only if leverage increases! But there are close links, thanks for pointing out the great project!

Snowdrift has people contribute as an increasing function of the # of co-donors, but the leverage, which is implicit, stays constant = 2, always (except for those cases where it even declines if others' chosen upper bounds are being surpassed), if my quick calculation is right (pretty sure*). This may or may not be a good idea with +- rational contributors (either way, I btw think it would be valuable for transparency to indicate this leverage explicitly to readers of the snowdrift page, it's a crucial factor for donors imho). Pragmatically it may turn out to be a really useful simplification though.

Here instead, Mutual Matching tries to motivate people by ensuring that they donate more only as leverage really increases. I see this as key innovation also relative to Buchholz et al. (maybe worth looking at that paper, it might be closer to snowdrift, as it also does not make donations directly conditional on leverage I think, tbc). As I discuss, this has pros and cons; the main risk being that the requested donation increases quickly with the leverage and thus with the # of participants.

Thanks to your links I just saw also the Rational Street Performer Protocol, which I should also look at, even if it equally seems to focus on donating more as more is given in total, rather than like here explicitly as leverage is increased; it makes the timing question very explicit, which is a dimension I have here not much looked at yet.

Will expand the text & make the connections to both asap!

*snowdrift: Each gives 0.1 ct per participant, meaning for 1000 (or 5000) you give 1$ (or 5$) and thanks to you all these others give 1$ (or $5) more in total than without you, i.e. extra leverage of constantly 1 in addition to your own contribution itself, meaning total leverage of your contribution = 2 always.