One of the most consistent mistakes I made when I was younger was to spend my time learning about things that other people thought were interesting —… - Paul Graham

As for building something users love, here are some general tips. Start by making something clean and simple that you would want to use yourself. Get a version 1.0 out fast, then continue to improve the software, listening closely to users as you do. The customer is always right, but different customers are right about different things; the least sophisticated users show you what you need to simplify and clarify, and the most sophisticated tell you what features you need to add.

It's a superpower to be interested in important things that most other people find boring. They'll do them out of duty, if they do them at all. So if you do them out of genuine interest, you'll get a lot further.

Twitter won't last forever. Nothing does. But whatever motivation ends up driving a successful "next Twitter," it's unlikely to be the fear that Elon will start allowing people to say heterodox things on the original Twitter.