Posted by Chris M. on 25 January 2012 12:08 AM
The core of WordPress is designed to be lean, to maximize flexibility and minimize code bloat. Plugins are like mini-applications that hook into WordPress to extend its functionality by offering custom functions and features. Plugins are developed separately from core by thousands of developers so that each user can tailor their site to their specific needs. You can use plugins for a wide range of functionality, including front-end things like adding an event calendar or shopping cart to your blog, or for back-end things like changing the way the administration panel looks or how you manage tags.
The following plugins are included with the WordPress core distribution:
Akismet checks your comments against the Akismet web service to see if they look like spam or not. You can review the spam it catches under “Manage” and it automatically deletes old spam after 15 days.
This is not just a plugin, it symbolizes the hope and enthusiasm of an entire generation summed up in two words sung most famously by Louis Armstrong. Hello, Dolly. This is, by the way, the world’s first official WordPress Plugin. When enabled you will randomly see a lyric from “Hello, Dolly” in the upper right of your Administration Panel.
The official plugin repository at wordpress.org includes many thousands of plugins to choose from, and has a rating system so you can see which plugins other users value the most. You can search for plugins by keyword or author, or browse by tags. It’s recommended that plugin authors include screenshots and a description of their plugins when submitting to the repository, but because plugins are developed by so many different people, there will be varying amounts of information available for each one.
With advent of WordPress 2.7, plugins in the official repository can now be browsed and installed from within the administration panel. In the left-hand menu, go to→ . You will be given the option to search by keyword or browse the tag cloud of popular plugin tags. If you are not looking for a specific plugin, try browsing by tag, as it tends to yield more results than keyword search in some cases. For example, if you are looking for more features around commenting, such as the ability to include video comments, you would click on the "comments" tag, which would lead you to a list of all plugins tagged with the word comments.
After looking through the list and finding one that sounds good, just click on Install. Depending on your server setup, the plugin with either automatically install, or you will be asked for your FTP information. If you are asked for this information, simply fill in and submit the form, and then your selected plugin will install itself.
Once the plugin has been installed, you will need to activate it. Go to→ and you will see a list of active and inactive plugins. Find the plugin you just installed, and click on the Activate link next to it. Voila! Your plugin is now activated.
In addition to the official repository that is accessible from your Administration Panel, plugins also can be found at the WordPress Plugin Database at wp-plugins.net. Not all WordPress Plugins make it into these repositories. Try searching the web for “WordPress Plugin” and the keywords for the type of functionality you are seeking. When obtaining plugins from a source other than the official repository, you will need to download the plugin and then ftp it to your server according to the author’s directions. Be safe! Before installing a plugin this way, check to see what people are saying online about the plugin (try the support forums, or a Google search) to make sure the plugin is legitimate and won’t do anything sneaky on your blog.
Plugins are meant to play nice, not only with the core of WordPress, but with other plugins. Most of the time, this is what happens, and users are able to install dozens of plugins (though the average is five) without any compatibility issues. Sometimes, though, a plugin’s code will get in the way of another plugin, causing compatibility issues. If your blog starts doing strange things, you may have plugin compatibility issues. Try deactivating all your plugins and activating them in various combinations until you find the culprit. If you find compatibility issues, please let the plugin authors know about it.
Plugin authors will sometimes update their plugins to fix bugs, add functionality, or to be compatible with a new version of WordPress (for example, a number of plugins needed to update their code to fit into the new navigational structure of WordPress 2.7). Plugins that are in the official repository will let you know when there is an update available. When you see a number appear next to Plugins in the left-hand menu, that means there are plugin updates available. Just follow the instructions and updating your plugin will be as easy as installing it was.
If you wish to stop using a plugin, you have two choices. You can deactivate the plugin but keep it installed, allowing you to reactivate it later should you decide you want to start using it again, or you can uninstall the plugin and remove it from your system altogether. You can also activate currently inactive plugins. For any of these functions, go to “Plugins > Installed”, and click the appropriate link.
If there’s something you wish you could do with your blog and you can’t find a plugin that includes that function, you might want to create one yourself. If you are proficient in PHP, you can learn about creating plugins in the Codex. If you’d like to collaborate with other developers, consider joining the wp-hackers mailing list, or hop into the #wordpress-dev IRC channel to find yourself some co-conspirators. If you are not a developer but wish someone else would make the plugin of your dreams, try posting it in our support forums.