What makes a good feature for a protocol-level subscription?

1. Features are enforced across clients — Snapchain, onchain contracts,  protocol fname and DC servers, etc.

2. Any app-level feature will create incentive for other clients to offer as a top of funnel "our client gives you this for FREE!". This is consumer surplus.

3. Ultimately, protocol-based social networks should generate a lot of consumer surplus in terms of what's available in the standard UX for most clients.

4. Conversely, it's tricky to add features that are 1) valuable 2) can be enforced at the protocol-level. 

5. An additional wrinkle is even clients can fudge protocol-level features (e.g. we support 900 character casts + a link for long casts and render them fully in our client; we link to a slideshow mini app but render the images in our client). This is why the protocol having a "official" client that is protocol-aligned and has high relative market share in the long run is good for the protocol.