Wordpress is without any doubt the biggest (open source) blogging platform. Well known for it's ease of installation, ease of use and of course the incredible amount of extensions that are available. Joomla! on the other hand is a very powerfull system made out of a fully object oriented (and pattern based) application framework, and on top of that the well known CMS. Joomla! is extremely extensible, thousands of templates and extensions are available. And while it is perfectly possible to create a blogging site (JFoobar is just an example of that), Wordpress is without any discussion easier to set up and use as blogging solution. It holds way more features by default for blogging then Joomla! In short, it is more difficult to create a blogging solution in Joomla! (although far from impossible).
Past week I joined twitter...not really certain how it works, but I must admit I have found some interesting information there so for now it seems worth while the effort. Today a post about combining Joomla! and Wordpress was posted on the corephp website.
Shortly after the creation of the Joomla! project the first core team used a Wordpress bridge for blogging, so the concept is certainly not new. In the mean while the core team blogs have moved to the leadership area on the community site using a very basic Joomla! installation and a professional commenting solution. The question is why you would use the Wordpress platform and an extension to bridge between the two?