A few years back I started working on a P2P-based social media app.

The things I did:

• Pull-based: you don't see anything from people you aren't subbed to.
• Natural vs algorithm-driven growth: Introduce friends instead of shoving randos into every conversation.
• No ads: Servers are expensive. P2P architecture removes (most of) them, so we can afford to run on donations of time and money.
• Community-based publishing: When you share, it's to a community of users you've curated. "Family", "Co-workers", "Cool co-workers", etc
• Community-based moderation: local + shared tags and filters to control what your communities can show you. (E.g. Block all #politics posts from Uncle Fergulous and all #soblessed posts everywhere. Sub to other users' tags to make them part of your personal moderation team)
• Data Ownership: I don't want your data. You host it. You own it.
• Right to be Forgotten: Automatically delete older posts (This is impossible to achieve completely, but having it as the default makes casual abuse harder)
• Pseudonymous: I don't care who you are. If the FBI cares, they may be able to track you though.