• Message Tags: Create your own tags to organize your email. Any number of tags can be assigned to the messages. Tags can be combined with saved searches and mail views to make it easier to organize email.
• Visual Theme: Thunderbird 2's theme and user interface have been updated to improve usability.
• Session History Navigation: Back and Forward buttons allow navigation through message history.
• Folder Views: Customize the folder pane to show favorite, unread or recent folders.
• Improved Support For Extensions: Extensions can now add custom columns to the message list pane in addition to storing custom message data in the mail database.
• Improved Offline Management: Thunderbird (Linux and Windows) automatically adjusts the offline state based on current network connectivity.
• Improved New Mail Notification Alerts: New mail alerts include information such as the subject, sender and message text.
• Folder Summary Popups: Mouse over a folder with new messages to see a summary of the new messages in that folder.
• Saved Search Folder Performance: Search results for saved search folders are now cached, improving folder loading performance. Find As You Type.
• Improved Filing Tools: Recent folder menu items to move and copy folders to recently used folders. Move / Copy again functionality.
• Updates to the extension system: The extension system has been updated to provide enhanced security and to allow for easier localization of extensions.
On the downside, the overall performance is pretty much the same: rather slow. The IMAP performance is still slow but then again, there isn't really an email program that provides a fast IMAP service. However, there are a few performance improvements such as the POP mail speed, which is excellent and even more, switching between folders, views and mailboxes is notably faster.
Unfortunately, this release is very beta. It can't be used fulltime, but by the looks of this early release, Thunderbird 2.0 will be worth the wait. Until the final 2.0 release, you can play around with this beta version and you can help the developers by reporting bugs.
Click here to download.