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I don't think that were XOOPS sites. On XOOPS you can add comments anonymously (without name) or registered (with name).
A hack for having anonymously names (contradiction) has been requested from time to time, but AFAIK doesn't exist. Problem is that the user in the comments is saved as a number (refferring to a registered user record) and there is no place to store a name in the database table.
In the guestbook, one can make comments about articles, but they are not 'connected' to the article as real comments are.