Overview by Gil Rutkowski, interesting comparison
A general overview:
Joomla is a full blown content management system. It’s an attempt to be everything to everyone and overall, it does just that. It has the ability to manage content in various styles and has a “front page” component that does a good job of displaying content in chronological order allowing it to emulate a blog. Over the last few years, it has evolved into a “framework” of sorts, allowing developers to rather easily use native functions of the CMS (Database abstraction, user system, etc…) to create native extensions and modules or port existing php software into Joomla extensions.
Content is managed in a rather ridged Section and Category taxonomy. Each content item can be assigned a single category and each category can be assigned a single section. Content can be displayed by section, category or in aggregate form and can be displayed in a few different formats including tables/lists and blog-style. Access to content can be controlled by a very basic group security scheme.
Templating can be as simple or robust as you’d like it to be. Both open source and commercial templates are widely available if you don’t have the skills or resources to create your own. Templates all consist of a main component “Content” area and unlimited “Module” areas and can be assigned site-wide, or by section and category.
WordPress is a simple and powerful blogging platform that has evolved the ability to manage content. It’s not trying to be everything to everyone but can be extended to most of the things Joomla can do. It thrives at blogging, but does have the ability to create and manage content pages. Like Joomla, WordPress also has a robust API allowing for developers to create native plugins and widgets or port existing php software into WordPress plugins.
Content is managed using a very flexible Category / Sub-Category taxonomy. Content items can be assigned to several categories and sub-categories and can be displayed by any of the assigned classifications. It also natively supports another taxonomy call “tags”. Tags are simply subject classifications and content can also be displayed based on it’s tags.
Templateing in WordPress, like Joomla, can be anything you make of it. Open source and commercial templates are widely available. Although the template structure and syntax is significantly different from Joomla, templates also consist of a main content area and unlimited widget (or module) areas. Recently, several WordPress theme “frameworks” have cropped up making templating more easily extensible.
Both platforms can probably do what you want them to do. WordPress is geared more to blog publishing, but can manage a pretty tricked out website. Joomla is geared more at people that need a corporate style publishing system and can run a full-fledged corporate site, but if you want to use it for a blog, it can definitely handle the job.