I remember reading his 2007 book, Exodus to the Virtual World: How Online Fun Is Changing Reality, and being fascinated by the idea that there were so many interactions between "the real world" and "the virtual worlds", with people "migrating" to virtual worlds because those provided more value to them than "reality", a reality that, in turn, had to adapt in order to recapture the attention of people. To me, the individual strategy of spending one's time in a "virtual world" because the "real world" fails to satisfy is one of "losers", and by "losers" I mean Hugh MacLeod losers as described in the Gervais Principle series by Venkatesh Rao. It is, in a way, a rational choice. (But let us remember that rational choices can be very wrong depending on the underlying premises.)
Edward Castronova suggests that virtual worlds left the front stage because they tried to be everything in one place and the trend is extreme fragmentation of functions.
It's interesting to reflect on why TN existed and why it went away. For a time in the last decade, there was a sense that an immersive 3D communal place was a substantial thing unto itself, and likely to become an important media offering. That has not happened. Instead, we've seen an unbundling of the parts of virtual worlds. Sociality went to Facebook. Complex heroic stories went to single-player games. Multiplayer combat went to places like DOTA and Clash of Clans. Economy games went to Farmville and the F2P clones. Virtual currency went to Bitcoin.
I wanted to state that Eve Online remains true to the "dream", though it remains a small game from a small company. The large scope of its features might be the drawback that will prevent it to ever rise to mainstream level, in the current state of the internet. (Inside the game, there is in fact a fragmentation of playstyles: some players use the game as a chat tool, others for pvp, others play the economy, etc.)
Perhaps virtual world designers were the latest incarnation of the utopian community builders of the 19th and earlier centuries. "If only we set up the rules correctly, people will naturally have a blast together!" No; I guess they won't. Not even if the utocrat can control physics down to the very atoms. Not even if the art and sound of the world is heavenly. Not even if people are given thousands of meaningful missions and wonderfully uplifting stories. Perhaps the mere presence of Others breaks whatever dream people are trying to have.
Funnily enough, the schadenfreude that permeates Eve Online, and that Edward Castronova's text hints at very eloquently above, is both key to the success of this game and a guarantee it will never be the game for everybody that World of Warcraft strove to be.
The utocrats in CCP, publishers of Eve Online, learned to let go a little bit. They know that they only co-author the game experience, which results from the actions of the players within the sandbox they designed.
TL;DR (too long; didn't read): if you are looking for a virtual world, try Eve Online. It can be a cruel place but it is uncertain that virtual worlds can be anything else... And the internet spaceships are real pretty.