The new project, code-named Lightning, aims to integrate Mozilla's calendar application, Sunbird, with its recently released Thunderbird e-mail application. That integration is aimed right at the heart of Microsoft's widely used Outlook software.
"I think Outlook leaves a lot of room for a fast competitor," said a Mozilla volunteer involved in the project, who asked not to be named. "There's a lot of user dissatisfaction out there, and it will be interesting to see what the market looks like once there's a strong open-source alternative."
After years of delays and miscues, Mozilla has made some market inroads this year with its Firefox Web browser. Web surfers have downloaded more than 12 million copies of the software since its, nudging Microsoft's dominant Internet Explorer browser for the first time in years, according to one survey.
Whether Thunderbird,, can have a similar impact on the Outlook juggernaut depends in large part on how quickly Mozilla can match some of the calendar features Outlook ties into the e-mail application.
Mozilla today released the first Sunbird 0.2 release candidate for Windows, Linux and the Macintosh.
Sunbird was donated to Mozilla by corporate volunteer OEone, now called Axcentra. The calendar has seen development in fits and starts, with more attention focused on it, now that both Firefox and Thunderbird 1.0 are out the door.
The mandate of Lightning, headed by longtime Mozilla volunteer and current Oracle technical staffer Mike Shaver, will be to integrate Sunbird features into Thunderbird so that users can do things like search across e-mail documents and calendar entries, and click a button to turn an e-mail message into a calendar task or reminder.
Mozilla isn't the only open-source group cooking up a potential Outlook competitor. The Open Source Applications Foundation (OSAF) is concentrating on an application called Chandler that is also focused on tightly integrated calendar and e-mail functions. Lotus Development founder Mitch Kapor is president of both Mozilla and OSAF.
Microsoft dismissed Mozilla's pretensions to its Outlook throne, noting that the vast majority of enterprise Outlook users rely on Outlook's integration with Microsoft's Exchange e-mail server.
"Thunderbird does not offer an equivalent comparison to Microsoft Office Outlook," Microsoft said in a statement. "Customers expect much more than simple calendaring and the ability to send and receive e-mails. The integration of Exchange and Outlook far outweighs any feature that Thunderbird may deliver, and we don't see it as being applicable for serious business use."
Mozilla engineering director Chris Hofmann said enterprise demand for Thunderbird was off to a good start and that an unidentified company recently installed Thunderbird on 44,000 desktops.
Mozilla, which posted information to its Web page about Lightning, plans a general release of some version of the software by the middle of the new year.