Unfortunately this was an insane week for me, so I didn't get to explore these tools in as great a detail as I would have liked - I never signed up for MySpace, although I plan to next week to see what all the buzz is about.
I could see the utility of these programs from a networking standpoint, although only if you post answers to questions about your profession and your unique skill set - rather than your biggest crush and favorite nail polish color. :-)
I'm having difficulty seeing it's utility for the library in terms of having a presence there - although again - perhaps I'm showing my age, which I didn't think was that advanced, but maybe in regards to this technology. The examples on our assignment page were more applicable to teens, doesn't seem like the grad students we deal with would have time or interest in this other than to share stories about med school or nursing school.
I can see privacy being a concern, but it seems that would be best addressed by the individual and how much information they put out there. I think like online publishing was, it's a new frontier and it will take time for some of us to embrace it and it's possibilities.
But I'm glad I am experiencing all these things since they are so in the news and used by so many - if I didn't have a class holding my feet to the fire I would probably never explore these things. So thanks!