What is the purpose of Second Life?

I have only just begun my exploration of this social networking device known as Second Life and I have to tell you I do not see the significance of it or how it relates in any way to teaching. First of all, the program is extremely slow regardless of which computer I am using at the time. I am not even able to edit my person without the program freezing multiple times. Don't get me wrong, I am up for trying it out, but the majority of the people on it are asking the same questions: How do you change your appearance? and what is the purpose of this network? Also, one question I have is how will this program help me to teach my students without using paper. Last time I checked, my school has been so fire-walled and blocked that it is completely impossible to even search Google for a map of the world. I understand the importance of socially networking with other people to gain new ideas and perspectives about teaching; however, I think it can be more easily done using Twitter.