Channel Insider content and product recommendations are editorially independent. We may make money when you click on links to our partners. Learn More.

The Mozilla Foundation will release late on Monday a full version of its open-source answer to the e-mail client.

With the launch of the Thunderbird 1.0 application, the nonprofit hopes to achieve in e-mail what it did with its Firefox Web browser: Persuade a groundswell of users to try its alternative to Microsoft Corp.’s dominant software.

Mozilla, of Mountain View, Calif., is initially targeting the Thunderbird release at consumers, particularly at heavy e-mail users, said Scott MacGregor, a lead engineer for Thunderbird. It hopes to parlay the growing base of Firefox users into new users of Thunderbird.

“If you’re looking at all the people moving to Firefox, we think there’s a subset of those people that are going to need more than Webmail but a richer experience, and that’s what we’re trying to offer,” MacGregor said.

Among its features, Thunderbird 1.0 provides a user-controlled spam filter, a built-in RSS reader and new approaches for managing and filtering through e-mail messages. It also can be used as a client for a range of popular, Web-based e-mail services such as the premium version of Yahoo Mail and Google Inc.’s Gmail that support POP3, MacGregor said.

But the foundation isn’t leaving the enterprise untouched. MacGregor said Mozilla plans to retool the application with enterprise-specific features in future versions. Currently, because it supports IMAP, Thunderbird works as an e-mail client with Microsoft’s popular Exchange server, MacGregor said.

Thunderbird 1.0 will be available as a free download for the Windows, Mac OS X and Linux operating systems. The full version release follows a series of preview, or beta, releases of the e-mail application. It is based on code from Mozilla Mail, a component of Mozilla’s namesake application suite.

Click here to read more about the last Thunderbird preview release.

Gaining converts for Thunderbird, though, will be tough for Mozilla, said Marcel Nienhuis, a messaging market analyst at The Radicati Group Inc., in Palo Alto, Calif.

“Most people are pretty happy and content with Outlook and Outlook Express, and [those clients] have most of the market,” Nienhuis said. “There’s this niche of people out there that want a little bit more. There’s maybe 2 to 5 percent of the e-mail population interested in that.”

In the enterprise, the executives who make enterprise messaging-system decisions are often reluctant to switch. Meanwhile, the client counterparts to enterprise e-mail servers, such as Microsoft’s Outlook client, often work best when used together, he said.

For consumers, switching e-mail clients also requires more setup effort than moving to a new Web browser, Nienhuis said. Mozilla notes that Thunderbird 1.0 includes migration wizards to move e-mail, contacts and settings from Outlook and Outlook Express.

For its part, Mozilla is betting that e-mail nuisance and privacy issues, like browser security issues, will cause users to consider Thunderbird as a Microsoft alternative.

MacGregor said Thunderbird 1.0’s spam filter can more quickly adapt than those in Outlook because it is controlled by a user flagging messages as junk e-mails rather than relying on files with filtering rules.

Thunderbird also attempts to block e-mail tracking by blocking the downloading of images containing embedded links when they come from unknown senders.

On the RSS front, Thunderbird includes a more full-fledged newsreader than Firefox. It lets users subscribe to XML syndication feeds and then read and manage posts like e-mail messages, MacGregor said. Firefox’s RSS capabilities focus on prompting a user when a Web page includes RSS and letting them save feeds in the browser’s bookmarks.

Click here to read more about RSS adoption.

Thunderbird does not integrate with Firefox’s RSS capabilities, though Mozilla is considering ways to link the applications’ RSS features, MacGregor said.

Thunderbird is one of the few e-mail clients with a built-in RSS newsreader. Opera Software ASA also supports RSS in its e-mail program. Outlook requires plug-ins from third-party developers such as NewsGator Technologies to act as RSS aggregators.

To manage e-mail, Thunderbird provides features called Saved Search Folders and Message Grouping. Saved Search Folders let users create e-mail folders based on a search query. Each time the folder is opened, the search is performed to find e-mail messages fitting the search criteria.

Message Grouping fine-tunes sorting by regrouping messages within a folder based on attributes such as date, sender, priority or a custom label.

Check out’s for more on IM and other collaboration technologies.