I remember this being somewhat talked about in 2005. It was like an alternative to Friendster. But no one ever made a feature from this. Is this still a thing?
It could be possible with nerds/geeks. However, that group (in the early 00s, at least) was far more interested in keeping their online anonymity prime and avoiding social networks; so I could totally see why it was dead in the water.
It might be this is a feature, not a bug. Making things easy did help a lot of people connect in at the start, but connecting in the careless also has hazards, much less the content casino digital media has become.
Among other things it ingested xfn (and foaf) so you could reasonably look for things like the connection between you and someone else who had a webpage, but the whole thing by itself didn't replace in any way what social networks were already offering, e.g. your feed, or direct messaging.
I think WordPress still supports xfn links, but it's not particularly useful.
It didn't get to that point, but there's a lot that could be possible if the graph were owned by everyone instead of just the social network owners. Distributed trust, moderation, etc.
That's imo the real reason semweb, microformats etc.. failed. We're left with a bit of schema.org that just plays into Google's SEO tactics.
by social networks i assume you mean specifically facebook, twitter etc and not IRC or any of the other pre-existing social networks that simply didnt have profile pages or comments sections
Today's webpages are mostly a big pile of javascript generated Single-Page-Application™
So no it's not a thing. The HTML is barely parsable.