Apple, Mozilla Plug Critical JavaScript Browser FlawsSource: cio-today.com
Critical JavaScript security flaws have been patched in both Apple, Inc.'s Safari Web browser and Mozilla's Firefox browser. But Mozilla and Thunderbird could be vulnerable in some instances. Apple also patched a flaw in Safari 3.1.1 for Windows.
Review: Thunderbird 2 e-mail softwareSource: Macworld
Thunderbird 2.0.0.13 has a very strong feature set, and does its job well; plus, if you are looking for an e-mail client that works and looks exactly the same on most of the different operating systems you may have to deal with, then Thunderbird's almost the only game in town.
List of programs associated with WHS bug growsSource: Ars Technica
The list of file types that face corruption on Windows Home Server if certain conditions are met has grown and may continue to grow, Microsoft says. The problem was first reported in December when Microsoft announced it could reproduce the corruption error with nine programs.
Mozilla Opens E-Mail SubsidiarySource: PC World
The Mozilla Foundation Tuesday opened Mozilla Messaging, a new subsidiary focused on developing its free, open-source Thunderbird e-mail software.

Another must have, especially for RSS in Thunderbird:
Stylish.
It works kind of like Greasemonkey in Firefox, an add-on that allows you to set CSS styles for everything or specific domains.

Well, if you've been following my column you'll have known the story by now. First, I fell in love with Thunderbird in May 2007. Then... disaster struck. See, I got kinda fed up with the speed issues and whatnot.
Cool Thunderbird Extension: MboxImportSource: nic-nac-project.de
This extension adds import/export controls for email files, such as that crap you get from forwards where it is an .eml file. This will import the file directly to whatever folder you want.
Mozilla Launches New Messaging Company, Thunderbird MailCo!Source: weblogs.mozillazine.org
Mozilla has been investing in email since the Foundation was created. We have a good, solid client in Thunderbird, and we have aspirations to do more. We ve spent the last few months working on how to meet those aspirations.

After a few months of toying with Thunderbird (in conjunction with Gmail, which I've had since July 2004), I've decided to remove it.
Reason 1: Speed
MoreColsForAddressBook Source: nic-nac-project.de
I can finally export my contacts to my iPod nano!
This extension for Thunderbird adds to the addressbook the following features:
Mozilla to push Thunderbird out of the nestSource: Ars Technica
In a blog entry written yesterday, Mozilla CEO Mitchell Baker discusses plans to create a new organizational structure for Thunderbird so that Mozilla can focus exclusively on the Firefox web browser.

The new version of Plaxo (Plaxo 3.0) was announced some weeks ago, with syncing capability across multiple applications (e.g. MS-Outlook, iCal, Google Calendar, etc.). Syncing includes contacts, – which is what Plaxo was doing initially – notes, tasks and calendar items.
Latest TBird 3.0a1pre Nightly has Tabs!Source: ffextensionguru.wordpress.com
The newest Thunderbird 3.0a1pre nightly (062707) now has tabs support. It doesn't work very well, but it is important to keep in mind TBird 3.0 is still in very early development (not even an official Alpha release yet).
Ten Open Source Apps You Can't Live WithoutSource:
A good list of popular open source applications showing how widely used open source technology is used on Windows, Linux and OSX.
List includes Firefox, Thunderbird, VLC...