Closed:

• Admissions, like Harvard. Gatekeeping, like journals. Selectivity is the name, like Nobel Prizes
• Most events, private gatherings, parties
• EAG. Metaculus. EA Funds.
• Benefits: you can create a reputation or brand for quality, which has virtuous cycles of begetting more quality.
• Problems with closed: running admissions is expensive. you may miss out on good people, because they don't apply or you fail to identify them. The winners have goodhearted on this.

Open:

• Everyone can participate. Church. Boy Scouts. Wikipedia.
• Anyone can enter tournaments like marathons.
• Taco Tuesday, the park, zombie tag
• Manifest. Manifold. Manifund.
• Benefits: you can farm, be agnostic about which approachrd are best, let everything grow and then hope the winners carry the batch. Cf black swan farming
• Problems with open settings: dilution of quality, misallocation of scarce resources, tyranny of doocracy (cf HOA)