By the end of this week, the Thunderbird 2.0 Release Candidate will be launched. Thunderbird is Mozilla's open source desktop email client, similar to Microsoft Outlook in features. However with the 2.0 release, Thunderbird takes on more Web functionality from the Firefox browser (more on that below). Thunderbird is cross-platform and it works on Mac, Linux, Windows - including support for Vista in 2.0. It was originally released Spring 2003 and now has just under 10 million users.

The 2.0 Release Candidate will be the final 'test' version before the full public launch of Thunderbird 2.0 by end of April. I spoke to Scott MacGregor, Lead Thunderbird Engineer, about the 2.0 version and what new features it has.

The 2.0 version of Thunderbird signals the first major upgrade since v1.5 was released in January 2006. There are a number of new Web features in 2.0, which is why we're covering it here on Read/WriteWeb. The main changes from 1.5 to 2.0 are message tagging (similar to Web tagging, as in or Flickr), new webmail integration with Gmail and Apple .mac, folder views and message alerts.

New Features

Scott said that Thunderbird's main goal is to address information overload for users. To that end, 2.0 has beefed up security and there are more customization options (i.e. add-ons, as with Firefox). It has also introduced the following email organization improvements:

  • Message tagging and improved search
  • Advanced folder views
  • Message alerts
  • Integration with Gmail and .Mac

Image: piratis

The tagging works similar to Gmail's labels, meaning you can tag each email with any number of keywords.

The Advanced Folder Views enable you to just display your favorite folders -with a toggle UI for easy management. For example you could choose to see only folders with unread messages.

The Message History Navigation is a concept taken from the browser - there are now 'back' and 'forward' buttons to view the history of an email. In relation to this, I asked Scott if there is a conversation view for email threads - as in Gmail, where incoming emails are added to previous emails in the same conversation (rather than a new email displaying each time someone replies). Scott said no, but they do have a threaded view.

Message Alerts is also new - meaning that every time a mail arrives in your inbox, an alert displays (if selected). I asked if this could be filtered - e.g. say I only want to get an alert when one of the R/WW authors emails me? Scott said that while you can't filter at that level, you can filter alerts via the usual email filters (i.e. by making certain emails skip the inbox).

The upgraded search allows you to 'find as you type' - another concept taken from Firefox. With Thunderbird 2, you can search across accounts (inbox, rss feeds, news etc). Also you can save your searches.

Thunderbird 2 has web mail integration (i.e. account setup support) for Gmail and .mac. Support for other Web Mail services is coming soon. The Web Mail integration probably could be taken further, because all it really does right now is improve the account setup wizard. But it does lessen the need to fiddle with POP settings, SMTP steps etc - so it's a welcome addition.


Probably the most interesting aspect of Thunderbird 2, from a Web technology point of view, is its customization features. As with Firefox, Thunderbird is an open source, flexible platform - allowing developers to create add-ons that extend its functionality. There are currently hundreds of add-ons, including contact managers, VOIP calling, and networking tools. The most popular, according to Scott, are Lightening (bringing calendar into mail), Plaxo (syncs address book, similar to Plaxo for Outlook), and enigmail (encryption).

I asked Scott for an example of an add-on idea that would specifically leverage the new 2.0 features. Scott suggested an add-on to sync tag stores with other apps (e.g. from Flickr into thunderbird, and vice versa). Sounds like an excellent idea, so somebody please 'make it so!' :-)

Scott also mentioned there are lots of add-ons that work across both Thunderbird and Firefox - e.g. FoxyTunes, a music add-on.


After my Gmail connectivity woes a week ago, and in the absence of offline functionality in Gmail, I'm pretty keen to get a desktop archive set up for Gmail. I had been using Outlook, but I'm now going to test out Thunderbird 2 - with its new Web features (tags, improved search, add-ons, etc).

If you are already a loyal Thunderbird user, please comment below on what you most like about it.