I'm developing a message board and I'm curious as to what I could get for it.

Advantages
-XML backend , which starts up if mysql goes down
-Templates
-Hash table caching system

Disadvantages
-No support for blocks
-Limited admin utilities

What language is it written in and what kind of custimization options does it have?

php 4


the templates can be easily changed from the admin interface
all the other options like categories, category load order, can be customized along with the standard elements like page title, etc etc from admin interface


the navbars have a seperate template if you want to intermingle the layouts

all messages can be edited by the admins

Well, you've got tough competition.... VBulletin.com is a very sophisticated software, you think you can do something better?

Anyways, good luck!