Not much difference in both... Joomla is a portal- or community type site while WordPress is a blog. this is the basic difference.
wordpress is user friendly and very easy to make blog while joomla is difficult. If you are newbie, start blog with wordpress.
WordPress is simple, you can see it as a blog or as a regular website. It has fixed pages, posts and categories. Joomla’s strenght is in complexity. Deep level navigation, sections in sections, categories etc…
The basic difference between WordPress and Joomla is that Joomla is a portal- or community type site while WordPress is a blog. Please visit more information- http://witsgroup.in/wordpress.html
You can do everything with both of them. You can expand Wordpress so much until it looks like a Joomla and reverse. Joomla is more complicated but seems to have more commercial plugins which are professional developed. Wordpress is, in my opinion, better for the end-user who wants to express himself. Conclusion: Joomla and Wordpress are created and developed by different organizations. Those are the biggest CMS you can decide between.
Wordpress is easy to learn and use, joomla is bit difficult... developer can easily understand and make changes in wordpress but not in Joomla.
Wordpress is actively developed (lots of themes/plugins), Joomla has way less. Drupal isn't even on the map.