That's not too surprising.
However my experience has changed in the last year or so.
Previously I was surrounded by many IT and academic people most days, who all knew something about SL.
Now, I meet fewer people, and with little or no knwledge of SL. Nonetheless they take an interest in "that game" Keith is "playing". What they want to know is simply what can you do with it, what does it cost, and how do you get started.
I've learned to keep it non technical, and probably not even mention SL or OS.
That seems feasible now, which it didn't a year or two ago.
The big drawback is still the need for a suitable computer and graphics card. However if a person now is looking for something to relax with, or explore, or they have a practical use for it, the cost of a used PC and a new graphics card is not that much, and a lot of people have pretty good broadband already.
This is a very small sample and not at all conclusive, however it does suggest there's a potential for many more people to benefit from this technology, if it is presented to them in a way that really is more accessible.