Complete shot in the dark but my brain can't let it be (also fuck it, thats the point of this topic):
Surfactants, specifically modern soap and soap products. I strongly suspect that petroleum based soaps cause damage and issues.
When you wash your glasses in a dishwasher, pour some water in after it is dried. Look at how many bubbles are formed on the surface. Pour it out and do it again - usually there will be less bubbles. That means you are ingesting leftover detergent that wasn't rinsed off. Can't be great for you.
I am more of a business person than a developer, so I approach it from that perspective.
I suspect that we will see different instances using different ways of paying for the service. It wouldn't surprise me in the least bit if there might be an ad supported instance, donation supported instance, subscription instance, etc. I think this is great because it puts power in the hands of the user to choose the experience they want. It should strongly encourage the design of a platform that prioritizes the user.
Right now things feel hacked together, but its inevitable that at some point performance issues, onboarding friction, and UX issues will be addressed. I really think its only a matter of time before decentralized platforms talking to each other take over.