My intuition is that browser plugins based on some federated system (e.g. Mastodon, Matrix) could enable this. Why complicate browsers even more? (No expertise here, so I'm probably missing the big picture)
To simplify it for normal people. My family all use browser extensions to block ads/tracking and shore up security because I set it all up for them. My non-technical friends don't. They understand video game mods because adding mods is fun. But the idea of modding other kinds of programs makes no sense to them, because those are for getting work done, not for tinkering with.
So in order for it take off, it needs to be presented as just a native feature of the web. In people's heads, the logic should go like: "My email software lets me forward emails. My calendar software lets me invite people to calendar events. My contact software lets me merge duplicate contacts. My web browser lets me annotate web pages with other people. What a strange world it would be if things didn't work like that?"
To simplify it for normal people. My family all use browser extensions to block ads/tracking and shore up security because I set it all up for them. My non-technical friends don't. They understand video game mods because adding mods is fun. But the idea of modding other kinds of programs makes no sense to them, because those are for getting work done, not for tinkering with.
So in order for it take off, it needs to be presented as just a native feature of the web. In people's heads, the logic should go like: "My email software lets me forward emails. My calendar software lets me invite people to calendar events. My contact software lets me merge duplicate contacts. My web browser lets me annotate web pages with other people. What a strange world it would be if things didn't work like that?"