Interesting /SecondLife thread from a young woman who left SL only 3 years ago, and now returns to a wasteland of WTF:
As a young woman (was 16-20 at the time), I made a lot of friends my age and had hours of large groups hanging out all the time. It was great! Now though? Everyone has left. Most of the sims we used to hang out on have completely shut down. The others are barren. I went on SL recently to see if I could find anything. All of the places that are populated are literally dance clubs, sex roleplay places, and Korea1. It seems as though all the younger players just don't exist anymore and it's all older people who are just into roleplay.
Some veterans who haven't left offer good advice -- like this from "DaemonBlackflag":
If you want to see floods of people, visit places like Collabor88 on the 8th of the month, or The Arcade on the 1st of the month in March, June, September, December. Most of the "welcome hubs" like Korea1 are just places people go to troll people. you'll find an interesting set of characters there... I see thousands of people all of the time involved with breedable pets, but i'm in a bit of a bubble.
This is, experientially all of Second Life feels like thousands of different bubbles, some overlapping, many not.