Performance: Caudium is a non-forking monolithic web server. Most web servers, like Apache 1.3, fork processes to keep up with demand, creating a less scalable solution when a sudden burst of traffic hits your web site.
An optional multi-threaded mode further increases performance especially when dealing with dynamically generated pages.

Templating: Caudium allows you to create site templates without much ado. You have several tools to aid you in that process:

• RXML - a HTML-like markup language.
• macros that can be defined either by the site designer or a programmer
• possibility to embed Pike code in your page to perform more complicated tasks or computations

Caudium also has a feature which is unique among the web servers - the supports database. Supports is a mechanism through which you are able to detect what features are or are not supported by the browser viewing your page. It allows one to create sites which use no JavaScript for browser detection. The visitor is handed clean and compact HTML pages not cluttered with JavaScript code. No need to mention that this feature makes the site far more browser-independent and flexible than when JavaScript is used to perform the tasks mentioned above.

Ease of use: All configuration actions can be performed through the web-based configuration interface: no more commands in the shell to type, no files to edit, no typos in the config file.
You'll use it to load new modules, check the status of your server or to create SSL keys.

Flexibility: You can write new tags and modules, easily extend Caudium using Pike or C and take advantage of the configuration interface.
Dynamic content can be generated with RXML, PHP or CGIs thus migration from other servers like Apache is very easy.

Platform independance: Caudium is shipped with Debian GNU/Linux and FreeBSD ports and runs on many other Unix-like systems (Any Linux®-based, OpenBSD, NetBSD, Solaris®, AIX®, Darwin/MacOS X®)
It is written in Pike and C.