good article and important topic - i have always been amazed at how casually many university professors, and even entire departments, busted into SL and developed university materials without concern for intellectual property
SL repsects your work but the killer thing is that they also reserve the right to use anyone's in-world work for themselves. no legal department from any US university would ever sign off on that condition
i digressed wildly from your topic but your technical precision is important and many people "think" they have permission but really don't (makes me think of another tangent with Amazon eBooks and the Kindle - you only have a limited license to those books and absolutely do not own them)