News that the total number of Second Life signups has breached the two million mark comes at a time when such figures are being heavily criticised.
Of course, the two million figure does not reflect the true number of SL users. But think of it as a proxy for the real number - a kind of SL index. The fact that the index has doubled in a couple of months is the real news; even with a retention rate of "only" 10%, it's the rate of growth that matters.
What we are seeing is Second Life and the virtual world idea begin to break through into the mainstream. Even if the two million number were "real" it would be footling compared to the size of the Net; but even 10% of it is not footling compared to zero.
As to criticisms it's VRML all over again - and speaking as someone who wanted to believe in VRML, but never quite could because it was so obviously limited - SL is something else, for a reason that has nothing to do with SL's technology, cool though it is.
Unlike ten years ago, broadband is available and relatively cheap today. I have a line that regularly gives me 4 Mbit/s and over for a very reasonable price; this means that I simply never have to think about bandwidth anymore. Speeds will continue to rise, and virtual worlds will be able to take even more bandwidth for granted, with a resultant improvement in experience.
If Second Life can do this well in today's computing environment, it will do even better in tomorrow's.