When you are logged onto IRC other users can retreive this information to see who is the person behind the Nickname.
The most straightforward thing to enter here is your first- and lastname or your email, however since IRC is pretty anonymous many people rather choose to be a bit more secretive.
If you want to do so, you may enter a motto, a pun or any line of text.
Any alphanumerical characters ,including the " " (space) are legal here. Total length must be less than 255 characters.