Internal Linking – click a button for an internal link and it allows you to search for a post or browse a list of existing content and select it for inclusion.Admin Bar – contains various links to useful admin screens. By default, the admin bar is displayed when a user is logged in and visiting the site and is not displayed in admin screens for single blog installs. For multisite installs, the admin bar is displayed both when visiting the site and in the admin screens.Streamlined Writing Interface – new users of WordPress will find the write screen much less cluttered than before, as more of the options are hidden by default. You can click on Screen Options in the top right to bring them back.Post Formats – meta information that can be used by themes to customize presentation of a post. Read more in the article Post Formats.
Network Admin – move Super Admin menus and related pages out of the regular admin and into a new Network Admin screen.List-type Admin Screens – sortable columns for list-type screens and better pagination.Exporter/Importer Overhaul – many under the hood changes including adding author information, better handling for taxonomies and terms, and proper support for navigation menus.Custom Content Type Improvements – allows developers to generate archive pages, and have better menu and capability controls. Read more in the article Post Types.Advanced Queries – allows developers to query multiple taxonomies and custom fields.Refreshed Blue Admin Color Scheme – puts the focus more squarely on your content.is_archive(); use is_post_type_archive() for full contextRemove WP_USE_MULTIPLE_DB. Introduce init_charset() and set_charset().Require an argument in wp_insert_post()Retire IIS 3,4,5 Set-Cookie redirection workaroundSave _wp_old_slug for all published post_type’s, brings old-slug redirection to posts and custom post typesSchedule update checks from an init hookSimplify sanitize_key() and use it in more placesSpecify feed type in the_category_rss()Split wp-includes/classes.php into single-class filesSupport custom post type links in wp_list_pages()TwentyTen Theme – Add ‘View Galleries’ link for post formatsTwentyTen Theme – Deprecate twentyten_remove_gallery_css in favor of the use_default_gallery_style filterTwentyTen Theme – Fixes header positioning in the IE9 betaTwentyTen Theme – Fixes to font issues in IE6 due to incompatible selectorTwentyTen Theme – Image handling adjustmentsTwentyTen Theme – Make sure we have a header image before showing itTwentyTen Theme – Use get_template_part() in single.php, attachment.php, page.php, onecolumn-page.php. Introduces loop-page/single/attachment.php. This is a backwards compatible change, as any child theme currently overriding single.php or loop.php will be entirely unaffected. Child themes can now override the loop in these files individually, by using loop-single.php, loop-page.php, or loop-attachment.php. (In loop-page.php, they can also usein_page_template()for the extra level of context.)Update Incutio XML-RPC Library to version 1.7.4Update jQuery to 1.4.4 (#15227)Update jQuery UI to 1.8.9Update TinyMCE to 3.3 (#12574)Update