Thunderbird 3.1 beta

Thunderbird, as a messaging system, is uniquely positioned as the tool that users can use to integrate as many of their communications as they want.
By combining an open architecture, a powerful extensibility and customization framework, and a person-centric perspective on communications, Thunderbird is a powerful yet enjoyable tool to help individuals manage their online interactions -- whether that's email, instant messaging, social networking messages, or other types of message.

Thunderbird will evolve to embrace the Web, by continuing to blur the distinction between what's on the web and what's on the desktop, while keeping in mind the importance of keeping the individual in charge of their online experience.