Since WordPress 2.8, we can target specific types of page views with CSS using the new
body_class() tag. Designed for use within the
body_class() outputs various class attributes according to the current type of page view. This makes it easy to apply page-specific styling such as current-page navigation highlighting and other nifty CSS tricks.
The whole notion of plugins is that they provide special niche functionality that not every site would need. But that is just theoretical, as most new features that have ever been added to the WordPress core began life as a plugin. If the plugin was useful to enough people, it was built in.
Out of the thousands of plugins available for WordPress, there is one that all WordPress users are familiar with: Hello Dolly. As far as I know, the Hello Dolly plugin was the first WordPress plugin and has been included with every version of WordPress. The plugin is so familiar that many WordPress users don’t even think about it. They either activate the plugin or delete it without giving it a second thought. But if you actually stop to think about it for a moment, the following questions seem inescapable: