WordPress Plugins are composed of php scripts that extend the functionality of WordPress. They offer new additions to your blog that either enhance features that were already available or add otherwise unavailable new features to your site.
The majority of WordPress users don't require Plugins, or only require a few, such as Plugins dealing with comment spam or customized post listings. Other users enjoy the varied options Plugins provide such as frequently updated weather reports, post word counts, rating systems, and more. WordPress Plugins are optional, based upon the needs of the user, and thus they are not incorporated into the core of WordPress.
Plugins available via the WordPress Plugins Repository designed by volunteers and are usually free to the public. WordPress Plugins hosted in the WordPress Plugins Repository are considered tested and "safe." Remember, WordPress Plugins are the responsibility of the author and the user, and they are typically works-in-progress as WordPress grows and expands.
