Jeremy yes agreed re the characteristics of resources, however the nature of avatars I see as a little more complicated.
In most online interactive envirionments there either isn't a visual representation of the contributor, or it's a static picture. Even if its a video its a snap shot of what that person says or does, what s/he looks like 'for real' on that day. Personally I try and avoid sending pictures until the group is well established- why introduce discriminators so early. However in SL the person is represented and in a way of their choosing. We can ignore this aspect or we can make something of it- what really matters to me is how it should be handled by (anotehr avatar- the SL moderator) to promote learning, knowledge sharing and the essential pre requisites and necessary conditions for these happy states.
Gilly