Here are the main improvements in Thunderbird 3:
• New filtering tools for research: the search results can now be filtered by sender, tag, or attachment, per person, per folder or mailing list.
• The autocomplete now works in the search bar with search in the address book.
• New configuration wizard email accounts with a greater database of suppliers, which can make presets.
• The toolbar for couriers has been improved, notably including Global search bar. The usual buttons as Reply, Forward, Delete or Spam are now present in every mail.
• The tabs now work like in Firefox: use the Enter key or double-click opens the mail in one window, while the click wheel opens the mail in a tab in the General window.
• Smart Folders are present by default in the left column. The Inbox allows eg to combine all the boxes of this type for all accounts.
• The selection of multiple messages to display a summary of the whole.
• The arrangement of columns can now be changed for each different folder.
• Creating an Archive folder which can drag emails from any other folder.
• The business manager can track all transactions between suppliers and Thunderbird e-mail.
• The extension manager is now as complete as that of Firefox, and therefore encompasses the extensions themselves, but also the themes and plug-ins.
• Contact Manager improved display with a star beside the name of a contact to indicate whether or not the address book and allow you to edit data quickly. You can also add a picture on each sheet, and include a birthdate.
• Better support for Gmail
• On Vista and Windows 7, Thunderbird can use the indexing engine built, which will display the letters in the research results from Windows itself.
• The haul IMAP are now downloaded in the background.
Regrettably, however, that more developers have not worked the interface, outside of the tabs and some controls, is precisely the same as in Thunderbird 2. Furthermore, the display "off" still offers a column of letters where all information is concentrated on one line. They also cite lack of management features offered by Windows 7 as the progress of an operation icon in the alert mail also received on the icon or the Jump Lists.