Virtual Worlds

What are the virtual worlds that've come and stuck around (so far) or fallen off the map? I know I've been to loads but I can hardly remember most of them; most never got out of beta. I've got vague memories of some I can't name - add any you think of to the comments. What was the one that recently appeared and was bought/closed before it even opened? I'm not adding things like Hello Kitty World for obvious reasons.

Exist Now
Second Life - US
All the Opensim SL-like grids such as Inworldz - various
FriendsHangout
Vastpark (maybe)
Twinity - German
IMVU (a lot of the There crew built this) - US
ActiveWorlds - US
Avaya (browser plugin like JLI - but you can sit/use voice, very business-oriented an avs have a built-in laser pointer) - NZ
Utherverse/RedLightDistrict (Is it around?)
Club Cooee (?)
Meez (?)
Habbo Hotel

Exist Now But Just Barely
Blue Mars (iPhone app)

Not Sure (sometimes I can get there sometimes not)
Just Leap In

Gone ;_;
There
Metaplace/Areae (Raph Kosterman) Downsized to a FB game Island Life
HiPiHi (I think) Chinese rip-off of SL
Kaneva (I think) Urban youth vibe
Nuria (or w/e it was called) Korean with great av interactions supposedly
Croquet (I guess) I used to check in periodically and run around as a rabbit - deformable reflections
Multiverse
Vivaty
Lively

One this the devs probably didn't understand: every time a place opened we'd stampede over out of curiosity and they probably thought, "Ooh! Tons of interest!" But it was just "us" - all the same people. I saw everyone I knew everywhere.