Well — I have read similar commentaries in a few places, so I thought I should leave my comment somewhere. None of the commentators will ever come close to donating the amounts involved here — so commenting on how self serving (or not) ones donations are is almost none of their business. If you cannot get hold of such large amounts of cash, your opinion on how it should be given away is moot. Second, so Mark is giving away his money the most efficient way he knows — based on what he has done so far, we can only assume that he will do a way better job than any government can. Third, Bill (aka Microsoft) to his credit has been extremely effusive of what Mark has done, he knows what it feels like giving away large amounts of money. His foundation (I am in no way knocking him down) has not been very efficient in giving away the money, the end goals have been murky and there is almost no way to make sure that the funds are deployed properly at donor organizations/countries.
So to the LLC itself, private enterprise is the best use way to disburse funds that I know of, you are held accountable for every penny spent. Investing in startups/organizations that contribute to the overall welfare of the society (environment/education/health/communication) is a laudable goal to achieve. A hybrid private investments/charitable donation model is the best model I can think of. There are places where a private company model will never work (schools, research etc) and there are places where a private model is the most efficient method to move the needle (clean energy, battery technology etc) — so a hybrid works best.
Lay of the non-sense about tax efficiency (because at the end of the day he still has to give away 99% of his wealth), and just appreciate how incredibly generous he has been.