Comments
From the Comments Module you can select certian settings that affect how comments are handled by members replying to posted articles.
You can select the type of moderation: By administrators, by the user membership, or to have no moderation at all.
You can also specify whether users who are not logged in can post a comment to a published article by selecting your choice from the "Allow Anonymous to post" item.
The "Comments limit in bytes" default setting of 4096 is probably good for most sites and prevents extremely long comments (which could present a perfomance issue for your database).
Lastly, one can set the default name for unregistered visitprs to the website. "Anonymous" is the default...but this can be changed to suit your needs.