That's true.

Site-local chat was meant to be the default way. But, was not restricted to that. People could keep whitelisted list of sites that they are open to get pings/DM's from.

I was still not able to figure out the privacy-focused, and local, interest matching part since it was meant to be p2p (without any server storage), and local storage can easily be tweaked.

If this was solved, my plan then was to automatically suggest people who may have similar interests depending on the sites they browse, for how long, and the messages they generally send.

Kinda like tinder, but, you don't have to sign-up and install no app.