Drupal Overview
Free 3d-party CMS.
Official site: http://drupal.org.
Advantages: templates control; system architecture; API; taxonomy; community.
Disadvantages: difficulty of working without preparation.
If you wish to completely control appearance and functionality of your site (level of control depends only on your desire), and thus not using dirty methods (like hacks of initial code of the core and modules) and to work only through API and extremely flexible template system – Drupal is for you.
In general, Drupal is first of all a constructor. The core contains only the most necessary — the lowest level which functions will be used in various modules. Basic Drupal installation already has many modules inside (such as blog, forum, search etc.). All is arranged very reasonably and smartly, and there are at least two ways to make what is necessary almost always. Sometimes this choice itself is a problem — it is possible to make all (or almost all) but a question is only what way to prefer (and what module to choose).
Due to this some beginners may choose another CMS, because it may take a lot of time to find the necessary module for a beginner.
Work with Drupal is like a breath of fresh air for the programmer (unlike Joomla, Postnuke and even Bitrix). A simple and clear code, powerful API, excellent documentation — what else do we need? The structure of the core assumes easy redefinition of the majority of core functions and modules (almost all which are responsible for output) with the help of «hooks». To write your own modules is very simple. Just a few of special functions in the filename.module file — and your module is ready.
You may think that Drupal is first of all designed for programmers. But this doesn’t mean that you won’t be able to make an individual and attractive site if you are a designer. If you don’t know PHP it is possible to install another engine (for example, Xtemplate) and work with it. And most likely it will not be necessary to write your own modules. It will be enough to go to the site and download the necessary ones (and the installation system in the new 7.4 version will make the process of new modules installation much easier).
What other advantages has Drupal in comparison with other systems? First of all — the unusual attitude to structure and content. In majority of CMS you define site structure through the menu at first, and then “connect” documents to sections. But the content is primarily in Drupal. You create documents, and then connect them with the help of unique taxonomy mechanism.
So how to apply taxonomy on the site? In the most elementary case it is possible to do news selections on different sections. Besides there are some modules which automatically build the hierarchical sections menu based on taxonomy. Thus anything can be a document (article, news, picture) and with the help of taxonomy everything can be structured and connected.
If you want more difficult applications it is possible to create a similarity of an online encyclopedia with automatic connections between similar pages (defined with tags), the mechanism of mutual links and several parallel filters for selections of necessary articles. Besides that a variety of external modules works on Drupal taxonomy. The part of them is responsible for access restriction, other can change site design depending on a category and so on.
It is possible to apply Drupal to almost any site type: from simple static sites (the system of pseudonyms allows to set any URL for pages) to complicated community-portals. There will be almost no restrictions in site design – it all depends only on the desire and experience of the developer.
Drupal has a built in system of internal caching which provides stable work even at overloads (slashdot and digg-effects). Besides you can automatically turn off the part of functionality at flow of visitors. I think drupal.org and theonion.com should be good examples.