Your IP, quite simply, displays your current IP address, as well as letting to press a button to copy it to the clipboard. Most useful for finding out your current IP address.
Note that if you are part of a local area network (LAN), you may have problems with it displaying the right address. (If it starts with 192.168.x.y, then this is your LAN address, and not your Internet address.)
This software was really quite lame, and was superceded with Your IP 2. You should actually use a service like http://www.showmyip.com instead of this software, if you really want to learn your IP.