Definitions

A Post is the basic unit of content you create for your blog. It is your blog entry. It corresponds to Joomla's Article.

Tags and Categories are ways of classifying your posts.

Categories have a hierarchy such that you could create a category called “Products” and then create another category called “Software” which was a member of products (a sub category?).

Tags do not have any hierarchy. A popular widget for WordPress displays a “Tag Cloud” of the tags you've used for your posts. This displays the tags such that the more frequently used tags are larger and or color coded. You can also customize how many tags to display and the sort order.

A WordPress Theme is the software which controls your WordPress design. It is analogous to a Joomla template.

A plugin is software that can be added to WordPress to extend its functions. It is similar in concept to a Joomla extension.

WordPress posts are presumed to be dynamic content. That is, content that is updated, changed, added to on a frequent basis. The default is to display posts on your WordPress home page, sorted by date.

A page, by contrast, is considered by WordPress to be static content that does not often change. An example of a WordPress page might be an “About” page. It is possible to customize pages to display dynamic content but in general this is not as easy as in Joomla.

Widgets are configurable components that can be added, arranged and configured in template dependent locations, usually the left and or right sidebar. Some examples of widgets which come with the default WordPress installation are Categories (shows categories available on your site and lets a visitor navigate to selected categories), Calendar (shows a monthly calendar indicating which dates have posts) and Recent Comments (shows the most recent comments to your posts).

Many plugins can be configured as widgets. Note that your template must support widgets to use them. Most newer templates do support widgets.