Posts are the entries that display in reverse chronological order on your home page. In contrast to pages, posts usually have comments fields beneath them and are included in your site’s RSS feed. To write a post:
In Joomla! an Article is a piece of content consisting of text (HTML), possibly with links to other resources (for example, images). Articles are the basic units of information in the content system and the bottom level in the content hierarchy. Since Joomla! 1.6 , each Article is in exactly one Category, and Categories can be in other Categories. It is also possible to have Uncategorized Articles that exist without being associated with any Category. In Joomla! 1.5 and earlier versions, an Article was the third level in the hierarchy Sections -> Categories -> Articles. Articles are maintained using the Article Manager (help screen) which can be reached in the Administrator (Back-end) by clicking on the Content menu, then the Article Manager menu item.
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