Theres no XML forum so I hope its okay to post here

Iam just wondering what can I use XML for in web stuff?

Eg. Iam going to build a menu system for my users that allows them to add links and remove links to the menu as they please, could I use XML to store this information instead of a MySQL database?

What other uses does XML have for websites , in use along side a MySQL database

XML is a way of storing data..
of course you can use it to store information instead of MySQL but remember that it will be much slower since you are dealing with flat files and then processing them..
also they can be exposed easily since they are normal flat files..

so the choice is yours .. XML is good, portable and very strict which is very good but it comes with the speed price.

ok thanks, I suppose its portability makes it a better choice instead of MySQL.

Could I use it as a theme engine? As in use XML to format the layout of the page , for the placement of php includes, so if I have a menu table, in one theme it would be displayed at the left of the page but in another its on the right side. The menu would be a php include file but could I use XML to format this layout in anyway ?

thanks

If your looking to do that sort of formatting, I think I would suggest using css before using xml to try and accomplish that. Like make different css layouts that display things/colours differently and so forth. I'm sure if you wanted to get into it and set yourself to it it could be done with xml but in terms of formatting nothing beats css.

One of the simplest uses of XML is to allow syndication of your site content, and even repost your content in your template. Done that, especially to show latest headlines on a news site, or a front page - ie:
http://www.chronicles-network.com/