I believe Rob had intended Hal to be used by different uses, I will give an example which would be the easiest way to explain this. The father installs Hal on his computer, the father talks with Hal about baseball and a few of the things he is interested in. The father has two children that are old enough to use Hal. One of the children talks with Hal and mentions that he likes chocolate ice cream. The other child talks with Hal and mentions that he likes vanilla ice cream. The temp file with the user name stores this information in Hal. In this method Hal can respond to each user knowing what to talk about and the likes and dislikes of the user.
I am pretty sure I had gotten this information from reading the forum, I am really not sure of the correctness of the information I provided. Best of luck with what you are trying to do.
Carl2