The basic alternatives are organization by place (the real world), organization by time (Twitter), organization by hierarchy (directories), and organization by search (Google). The recent interest in organization by place may reflect that organization by time has led to endlessly scrolling lists of drivel. Or a hierarchy of same, like Discord.
It's amusing that people are using Animal Crossing - New Horizons as a social system during lockdown. (Classic Animal Crossing models another current problem - when you go into Animal Crossing, you're broke and alone, and then it gets worse because you have to borrow money, then work your way out of debt.)
For social purposes, and for business purposes, you may want some sense of place without a full 3D world. It's possible to hold a business meeting in Second Life. There are conference rooms available. People can leave the meeting, walk around, and meet casually with others. There's directional and position specific audio. Around 2008, this was more of a thing than it is now. It's getting something of a comeback as people are locked down and want a little more in-person contact than you get over Slack.
Second Life's mapping to the real world is a bit too realistic - you can get a slide projector and show your PowerPoint files, with slide changing noises. Someone going between projector and screen will cast a shadow. You can have people in suits. Very good looking photorealistic people in good suits if you pay for a good avatar and outfits. You can have coffee service and a bar if you want.
It's the metaverse, like Ready Player One. (Except too sluggish under load, something slowly being fixed.) It looks great, but overkill for most people who aren't regular Second Life users and know how to drive the thing. Here's an actual meeting in Second Life.
Facebook took a crack at this with Facebook Spaces, which was a flop. They shut that down and announced Facebook Horizons in late 2019, which may have been abandoned or postponed.
We have seen massive growth on https://hubs.mozilla.com which can be self hosted https://hubs.mozilla.com/cloud