This project should improve my abbilities to program in php/mysql/html/xml/js/css + project-management
So I try to include quite new ways of programming. But also I care about performance.
And another concept is, to avoid incompatibility with user agent or webservers (but today php5 is already recommended, cause it exists for a very long time and i don't want to add on every php5-command a fork to commands of older php-versions)

Actually the team is quite small and i do the most of the work. So i'll use in the following only "i".. maybe hopefully later i can change it to "we"

Some perfomance improvements in this code:
-not much oop, cause it is often to much code to compile which slows the page down..
-mysql-queries can be buffered and will be sent in one query (with the help of the mysqli-extension)
-bbcode is precompiled in the db (ok maybe i'll change this later.. but actually it improves performance)
-i try to keep the html-data small, so i use not much tables and already use the yaml-framework
-i added the possibilty to compile the template with code-compression, which removes unneeded slashes or tabs
-i use a template-c
-ajax loads only parts of the data

Other cool things:
-i mod_rewrite every url through the template-compiler if it's needed (it's a quite cool way.. you can write your urls like all the time before and the tp-compiler transform it for you to your mod_rewrite.. and if you don't need mod rewrite, it can change & to &/&)
-i wrote a funcion, which follows your includings and at the end you can see in the debug-console what are the parents of the included files and how many includes you do per page.
-i wrote some mysql-functions, which tell you how much queries you performed, how the performed queries looked like (it's very good for debugging) and also it shows the execution time of every query
-we have a good right-management which provides much functionality and is very easy to include (but already the admin overview is not so good.. so the features are not that big as it's possible.. but we have the chance to expand them)

accessibilty:
-we try to validate our code with the w3c-standard.. and nearly every page is valid..
-the user can decide wether he likes to use javascript or not (it's only activated on some pages where i can't provide an alternative way to javascript.. but js is never recommended)