In Liberal Radicalism: A Flexible Design For Philanthropic Matching Funds, Vitalik Buterin, Zoë Hitzig and E. Glen Weyl propose a mechanism for (near) optimal provision of public goods.
The paper is quite recent (December 2018). Considering that the EA community may be vetting-constrained, has anyone implemented or considered implementing the suggested mechanism?
MIRI took part in a Liberal Radicalism-based fundraiser at the end of 2018 (see "WeTrust Spring" in this post).
The main issue with the mechanism seems to be collusion between donors. As Aaron mentioned, MIRI took part in such a fundraiser. I claim that it was so successful for them precisely because MIRI supporters were able to coordinate well relative to the supporters of the other charities -- there were a bunch of posts about how supporting this fundraiser was effectively a 50x donation multiplier or something like that.
MIRI helped us know how much to donate and how much of a multiplier it would be, and updated this recommendation as other donors made their moves. I added something like $80 at one point because a MIRI person told me it would have a really cool multiplier, but not if I donated a lot more or a lot less.
I haven't heard of anyone implementing something like this. I think it's a great idea – would love to see more exploration of it!
IIRC, the mechanism has problems with collusion/dissembling. For example, one backer with $46 dollars and 4 backers with $1 each will get significantly better results by splitting their money into 5 contributions of $10 each. This seems like a problem that's actually moderately likely to arise in practice.
MIRI helped us know how much to donate and how much of a multiplier it would be, and updated this recommendation as other donors made their moves. I added something like $80 at one point because a MIRI person told me it would have a really cool multiplier, but not if I donated a lot more or a lot less.