We have experience working with Wordpress to setup blogs and as a CMS. We know a lot of really useful plugins to install and ones to avoid that use a lot of system resources and will slow down your site. We have setup social networks using Buddypress, galleries, shopping carts, and more using Wordpress software.
We can integrate a Joomla and Wordpress site using software created by corePHP. We can also setup Wordpress MU, which is open source software that allows multiple users to create their own blogs, and can be used to allow free blogs for people who sign up for membership.