The most important ones:
- Global undo/”trash” feature: If you accidentally delete a post or comment you can bring it back.
- Built-in Image editor: Say goodbye to offline editing and then uploading images. The new builting editor crops, edits, rotates, flips, and scales them in a snap!
- Batch Plugin Update: No more individual plugin compatibilitiy checking/ upgrading. One click and all are done.
- Better Video Embedding Any URL from YouTube, Daily Motion, Blip.tv, Flickr, Hulu, Viddler, Qik, Revision3, Scribd, Google Video, Photobucket, PollDaddy, and WordPress.tv are automatically changed to appropriate Embed code.
- Better SEO:
rel=canonical,
Specify category templates not just by ID, like before, but by slug, which will make it easier for theme developers to do custom things with categories — like post types!
-
Automatic database optimization support: Enabled by adding
define('WP_ALLOW_REPAIR', true);
to
wp-config.php
file.
- Themes now can register Post Thumbnails (Like DZone)
- Upgraded TinyMCE WYSIWYG editing and Simplepie.
- Better hooks and filters for excerpts, smilies, HTTP requests, user profiles, author links, taxonomies, SSL support, tag clouds, query_posts and WP_Query
There’s more, you can check them on the official blog.