In this article Wagner James Au writes about some of the pressures and expectations that everyone is expected to be American in Second Life. I personally have not found it to be a barrier, though I have been happy to express the fact I am a brit. Indeed there are many groups such as Brits in SL who are clearly not just US based. Our eightbar group in SL by its very nature crosses many cultures as the interest in Second Life spans further than us in Hursley and across IBM.
I have also found that in general people are quite chilled out and polite about things. SL is more of a leveller in terms of culture. Though given it is a ‘english’ focussed language based medium I am sure its NLS support will grow. Who knows we may even be able to learn a bit more about one another’s cultures through this medium more than any other?