Of all the speculations that can be made about secondlife, there is one of which I am certain: secondlife as we know it now is destined for a necessary and radical change, which will make this type of application take off.
I am speaking about the way in which the project is owned and run today as the private property of Linden Lab. Here is a link to the company overview page: http://lindenlab.com/press/overview.
I am not able to imagine that a similar project can evolve very much, since it remains in the hands of a single company; the problem is in managing a thing of such enormous complexity.
At least the history of humanity shows us that above a certain threshold of economic, political and social complexity, a community must formally separate political power and the other powers, as is happening in China or Vietnam.
This is not an ideological argument but a technical evaluation of possible management models.
Today secondlife is an environment with very few rules, all decided arbitrarily by the board of directors and the executive management of Linden Lab, in the interests of the firm shareholders, who in my opinion understand the problem very well, given that so far, they have shown great foresight.
If Linden Lab know how to run this process, it will remain the main protagonist for a long time, otherwise it will be crushed by the development of another secondlife environment having resolved this phase; a solution, perhaps the only one, could be to open the standard to anyone who supports the technical interface - meaning anyone will be able to run the servers and decide the rules connecting to a network of servers.
Everyone together will form the secondlife universe and each of us will be able to have our own server, just as every one of us has an intimate and indivisible individual sphere.
Another phase that we will rapidly see will be where a secondlab provider will decide that the rules can be decided by the citizens through voting.
It will be interesting to see which evolutions these neo-democracies will have, that rapidly overtake the efficiency of the democracies we know today. Just think of being able to vote not once every five years but continuously, drastically reducing political intermediation.
Technically, it is not impossible to imagine this in a community necessarily literate in the use of the information technology.