Mozilla's CEO has denied that Google pressured it into dropping development on its Thunderbird email client.

Several comments posted to Mitchell Baker's blog linked Mozilla's decision on Thunderbird and Google's push into web-based email with Gmail.

"Since Google is a primary funder of the Mozilla Foundation, and since Google is actively developing and offering their own enterprise-grade email ecosystem via Gmail and Google Apps, maybe they are wanting to kill off or hinder the development of Thunderbird to 'encourage' those wanting to ditch the Outlook/Exchange juggernaut to move to Google," wrote a user identified as Vaughn Reid.

Reid was responding to Baker's disclosure that Mozilla, the commercial development arm of the non-profit Mozilla Foundation, would shift Thunderbird to another entity and focus exclusively on Firefox, the open-source browser.

A few others took up Reid's claims. "Maybe my tinfoil hat is just wrapped a bit too tight today, but what's the odds that Google pressured the MoCo [Mozilla Corp] folks to simply cut ties on the standalone Thunderbird mail client, since they (Google) are trying to move the average home user to web-based Gmail, anyway?" asked Marc Rust in another comment.

Baker said that simply wasn't true. "I want to be as clear as possible about the complete lack of Google involvement," Baker wrote. "Google and Google products had nothing to do with this decision, we did not ask Google about Thunderbird product planning, Thunderbird revenue, Gmail product planning or Gmail revenue, and we did not ask Google's opinion.

"Google's plans for Gmail - whatever they are, and they are unknown to me - are irrelevant to this decision," she said.

As Reid noted, Google is the major source of Mozilla's revenues. A partnership that sets Google's search site as both the default home page and search engine in Firefox pays Mozilla millions annually. The last time the numbers were made public, Google paid Mozilla approximately $52 million in 2005. (Mozilla has not released its 2006 tax return.)

Mozilla is considering three options for Thunderbird, including releasing the software to its own community, a la SeaMonkey, which has been met with both dismay and understanding by users commenting on Baker's various blogs.

The two lead Thunderbird developers, Scott MacGregor and David Bienvenu, have put their support behind the idea of a small, independent company that would continue work on the emailer with lots of help from the unpaid developers who now contribute to the coding.

MacGregor said in an email that he and Bienvenu wanted to keep Thunderbird alive. "We and our community are not going away." He also promised that whatever organisation is formed to support the software, work on the next update, Version 3.0, will continue. "There will be a next major version of Thunderbird," he said.

No timetable has been set to decide how Thunderbird will be separated from Mozilla, MacGregor added.