XOOPS' comments system is kind of a let down for anonymous users as it doesn't allow for them to enter a username. It's fine for those who have accounts but if you're running a site that doesn't allow accounts it means that there is no way to identify posts from anonymous users unless they conciously put their name at the end of the post.

What the comments system needs is a couple of extra fields that allows users to enter their name, website address, and then their comment as well as some ability to save these details for the next time they come to the site.

Just a suggestion.