While Firefox is the most important open-source Web browser and is now at version 3.0.3, Thunderbird is still at version 188.8.131.52 and now its first 3.0 upgrade has been delayed. Rather than release the Thunderbird 3.0 Beta, as had been the plan, Mozilla Messaging, the division of Mozilla developing Thunderbird, has decided instead to release it as Alpha 3.
Mozilla Messaging is doing this because, Dan Mosedale a Thunderbird developer, said in his blog, "Calling something a beta is likely to trigger a bunch of extra press attention that we're not yet in a position to deal with. Some number [of] reviews will be inappropriately pre-judging [Thunderbird 3.0] based on its current state. In the best case, this would be a distraction."
In other words, it's not close to being ready. Mosedale went on, "While we've been pretty clear for a while that calling something a beta doesn't mean that we're feature complete, what we've got now feels like it's pretty far from being representative (from a user-experience and user-visible-change point of view) of what Thunderbird 3 is going to feel like." In other words, really, really not close to being ready.
If you know the history of Thunderbird, it's easy to see how this happened. In July 2007, Mozilla CEO Mitchell Baker admitted that Thunderbird was coming in a distant second to Firefox at Mozilla. At the time, Mozilla wasn't at all sure what to do with Thunderbird. Baker wrote, "We have concluded that we should find a new, separate organizational setting for Thunderbird; one that allows the Thunderbird community to determine its own destiny."
That said, Mozilla didn't know what to do with it next. A few months later, in September 2007, Mozilla spun Thunderbird's development into a company of its own. That company got off to a very slow start. In fact, it would be fairer to say that it stalled out.
In February 2008, for example, some security bugs were discovered in both Firefox and Thunderbird. Those problems were fixed promptly in Firefox, but, while it was reported that they were fixed in Thunderbird, they actually were not fixed until a later version of the Thunderbird. This trend continued through 2008 to date. For instance, several Firefox security problems were fixed in the late spring and summer, but were only fixed in Thunderbird in July 2008.
Clearly, things haven't changed. Thunderbird is still a distant number two to Firefox. I think that's a shame. I've always preferred e-mail clients to getting to my e-mail via a Web browser. Or, perhaps, I'm in the minority and Web-based e-mail will be what everyone will be using in the future. These continued delays in Thunderbird's development certainly show that's how Mozilla sees it.