What are the ways to p2p comment on web pages?

Question

Browsers

I'm not sure, but once there was an article on Habré about a browser extension that allows its users to write comments on any pages. The user enters the page, writes a comment, everyone else who is viewing the same page at the same moment receives a message.
I want to evaluate what options with similar functionality are now available, but I just can’t find at least one.

Answer 1

Do you remember this thread by any chance?