Random thoughts:
1. You can already quote notes
2. It may be potentially socially disastrous to have the ability to link random notes in some official capacity outside of @ mention or repost. Maybe the notes were meant not to touch each other (author doesn’t want you to know what obviously motivated them to post that)
3. I don’t know if social media was ever meant to be productive? You’d want to turn all of this off if you wanted to get something done. In terms of learning functional threads would be a better solution I think (not related to your comment but I’m just pointing it out)
4. In terms of organizing information, I think visual bookmark boards or even lists would do a decent job if they are well designed and invite exploration.