Last checked and updated on 13 Jun 2026
What Is New in WordPress 3.0
| Category | Key Changes |
|---|---|
| New Features | New Default Theme (Twenty Ten), Custom Post Types, Custom Taxonomies, MultiSite (Merge with WPMU) |
| Improvements | New Menu Management System, Author Templates, Shortlink API, Bulk Update for Themes |
| Developer APIs | Custom Backgrounds API, Custom Headers API, New get_template_part() function |
| Bug Fixes | Numerous fixes across the core platform |
How did the merge with WordPress MU change things?
WordPress 3.0 merged the codebase with WordPress MU (MultiUser), making multi-site functionality a native part of core. This was a huge shift. You no longer needed a separate project to run a network of sites; you could just enable it from a single WordPress installation.
In practice, this meant the is_multisite() function and the entire Network Admin area became core components. This move unified the community and set the stage for managed hosting platforms as we know them today.
What can you actually do with Custom Post Types?
Custom Post Types (CPTs) let you go beyond standard posts and pages to create entirely new content structures. Think portfolios, products, testimonials, or events-each with their own admin interface and editing experience.
You register them in your theme's functions.php or a plugin using register_post_type(). This was the single biggest feature for developers, finally allowing for proper content modeling directly within WordPress without ugly hacks.
How does the new menu system work?
The new menu manager provided a drag-and-drop UI for building navigation menus. It replaced the old method of hardcoding page lists or relying on theme-specific options. Users could now mix pages, categories, and custom links effortlessly.
For developers, it introduced the wp_nav_menu() function and theme support via add_theme_support('menus'). This standardized menu output and made themes infinitely more flexible for clients.
Why was the Twenty Ten theme such a big deal?
Twenty Ten was the first default theme to truly showcase WordPress's new capabilities. It was built to demonstrate features like custom backgrounds, headers, menus, and post formats right out of the box.
It set a new standard for theme development, proving that the default theme could be both powerful and elegant. It became the foundation that many future default themes would build upon.
FAQ
Is the MultiSite feature enabled by default after the merge?
No, it's not enabled by default. You must manually enable it by defining MULTISITE as true in your wp-config.php file and then running the network setup process.
Can I use Custom Post Types with existing categories and tags?
Yes, by default, custom post types support the standard 'category' and 'post_tag' taxonomies. You can also register custom taxonomies that are exclusive to your new post type for more granular organization.
How do I add support for custom menus in my theme?
You need to declare theme support using add_theme_support('menus') and then register menu locations with register_nav_menus(). After that, you can call wp_nav_menu() in your templates.
What's the proper way to include a template part?
Use the new get_template_part() function. For example, get_template_part('loop', 'index'); will look for a file named loop-index.php. This is cleaner than using traditional include statements.
Does the Shortlink API create a permanent link?
Yes, the shortlink generated by wp_get_shortlink() is a permanent redirect (HTTP 301) to the full post URL. It's designed to be a persistent, compact URL for sharing.