I don't really know that much of either, although I know a TINY bit about XML.
As for whoview... When you use "[ whoview ]" in a post or somesuch (without the spaces between the brackets and the word), it will show the screenname of the person viewing the post where the [ whoview ] is. An easy way to tell if it's a whoview trick is to select quote from the drop down menu beside that person's post. You should be able to see how it's done. It's that simple, right ?