Your Personal Information, is the information that appears, when someone clicks your user name.
This can include anything, from personal information about yourself, to information about your computer.

To add personal information:

At the top of any page, click My Controls.
On the left, under Personal Profile, click Edit Profile Information.
Add as much, or as little information, as you feel comfortable with.
When your finished, click the Amend my profile button, at the bottom.