Both Joomla and WordPress are established web design applications used by millions of websites across the world. Web Design Companies and web designers have in general supported various open source software for developing websites. Joomla and WordPress are two of the most popular ones and have established communities on the internet. There are hundreds of quality forums and blogs dedicated specifically towards the use of Joomla and WordPress for designing websites. Other web design and content management systems including Drupal and Typo3 have also proved popular and effective. However WordPress and Joomla seem to have an edge over the others in terms of global popularity and use.
WordPress v/s Joomla
Usability
WordPress probably scores higher in terms of usability, both from an end user as well as developer's point of view. Due to its simplicity WordPress is easy to learn and get acclimatised to. However this is also due to the fact that Joomla offers many more features than WordPress and offers more advanced functionality. The new version of Joomla, the 1.5x version has made significant improvements in usability.
Versatility
WordPress is better described as a blog software whereas Joomla is an advanced content management system. WordPress is excellent for publishing content. Joomla on the other hand offers many powerful features. There are Joomla components that target almost every industry and market.
Search Engine Cptimization
WordPress is known for its search engine optimisation advantages. By default WordPress is search engine friendly and webpages tend to rank high on Google. On the Joomla needs some customisation in order to target the full benefits from search engines. With the right customisation however, Joomla websites are equally capable of ranking high on search engines like Google. Any expert Joomla developer will design a website to be SEO friendly.
Scalability
Joomla is easily scalable. Joomla can be used to design small websites as well for developing complex functionality on websites. WordPress is great out of the box and will work excellent if the only purpose of the website was to publish informational content. WordPress is great out of the box but limited somewhat for developing complicated web applications.
Integration
Joomla has clear advantages with regards to extending and integrating the website with other third party applications of software. Joomla has a well formed and powerful API that developers can use to extend the software or integrate with other systems as required. Joomla websites can be easily integrated with other sources or websites.