Retrieves the username of the current user.
Returns the username as a string.
If the user is not logged in, evaluates to the string anonymous
.
This markup displays user variables on a page:
<$if UserName$> Logon Name: <$UserName$><BR> User Name: <$UserFullName$><BR> E-mail Address: <$UserAddress$><BR> Default Account: <$UserDefaultAccount$><BR> <$endif$>