Fc is on other end of spectrum, so different challenges. But from that list I would say app signatures. Provides trustworthy way of verifying that a message came from trusted client, which is helpful for mitigating spam and filtering out messages from malicious or low quality clients.

Idea comes from pain point with indexing content from Lens. We selectively index content posted from more reputable clients (Phaver/Orb/Lenster), but no way to verify content was actually published from either of those apps.

yes! we want to build something like this

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