EveryBlog is meant to be a replacement for the default Drupal Blog module.
May 25, 2009: EveryBlog is pretty much tabled as the core functionality is easily implemented using views and taxonomy, this site for instance is using taxonomy for both tagging posts and placing them within specific "blogs" and then views are used to display matching posts. Hence the overhead of an entirely seperate module is not needed as it is fairly easily to do using existing solutions which are likely to be far more stable due to their larger development community.