Well…on the non-sexy, non-neo-cyber-goth side of Second Life, they are apparently building virtual museums. Neal Stephenson could have warned us about this.
From a paper given at the Museums and the Web 2007 conference:
Exploratorium staff members have created… a space in the massively multi-user, three-dimensional world of Second Life. In the virtual museum called the ‘Splo, we’ve been experimenting with the social, contextual, and educational possibilities of a world in which people can fly through the solar system, scan their own bodies, and change gravity so they can bounce off walls.
Wait, wait, think of the fund-raising and naming opportunities!

2nd life vs. 1st life:
http://www.nytimes.com/slideshow/2007/06/15/magazine/20070617_AVATAR_SLIDESHOW_1.html