How do you know what your "name" is to share files?

[Lord of the Rings]

I have never used the private sharing option of LW 5. The names given users are based on their ip address & helps to mask their ip address for privacy.

To use private sharing, I believe you first need to log into GMail or similar first before you can use it. That's the limit of my knowledge on the topic. How to find out your friends LW name .. I do not know.