1. You connect to friends and you either manually assign or "grow" a bunch of weights to your amount of trust in them and your interest in various topics they might post.
2. You and your friends make posts and assign "topic" metadata to the posts. The value of the system depends on your friends properly assigning metadata to posts. But it makes it easier to filter out extended families' political shitposting (based on trust and negging untagged posts).
3. Your feed is selected based on the weight of your friendship times the weight you base on the interest of the topic. If your best friend posts something about computers and you have positively weighed that topic it would bubble up.
4. Friends-of-friends can transitively receive a proportion of the trust score you have in your friend. Highly trusted friends will make you trust their friends more.
5. Down-votes and upvotes would train your local agent. They could also be fed back to the originator IF votes were signed by trusted encryption keys to prevent your friend from faking his vote count on the "post".
This decentralizes the network out of FB and democratizes the algorithms / system for what and how you want to receive your information.