Over the last three years, an average of 85% of the Mozilla Foundation's revenue has come from search engine partnerships, most importantly from deals that enable the Firefox browser to use its search bar to use Google by default. Though Mozilla's relationship with Microsoft's Bing has grown strangely closer over those years, Google - the maker of the competing Chrome browser, which was created using much of Firefox's braintrust - has remained the principal search tool for Firefox. That tool alone, one analyst said last year, may be responsible for just over 9% of all Google searches.

The last partnership extension between Google and Mozilla - a three-year deal renewed in August 2008 - was apparently allowed to expire last month. This led journalists including my friend and colleague at ZDNet, Ed Bott, to wonder whether Mozilla had any kind of Plan B. Today, we're being told that something resembling a Plan B (or C or D) may be in the works.

A Mozilla spokesperson told ReadWriteWeb yesterday evening that the Foundation and Google remain in talks, apparently over some type of search partnership.

"Our search relationship with Google remains positive for both of us," the spokesperson said. Though the statement continued by saying there was nothing further to announce, there was: "We have every confidence that search partnerships will continue to be a strong and growing generator of revenue for the foreseeable future." The organization may have something further to announce later this month, we were told.

That last sentence, which does not include the word "Google," indicates that while a deal may indeed be finalized with someone this month, that someone may not necessarily be Google.

The two major search providers, Google and Microsoft (the latter having already begun providing results for Yahoo), are of course in a position to not only feed Mozilla's hand but bite it. While both Firefox's and Internet Explorer's usage share worldwide has been very slowly dripping away, Google Chrome's share has been on a steady rise. Judging from NetApplications' numbers, seen here, Chrome is on its way to overtaking Firefox's #2 position in usage share in Q1 2012.

Contributions from search partnerships with Mozilla would hardly be a burden on either company. According to the Foundation's 2010 financial statement, "The Corporation has a contract with a search engine provider for royalties which expires November 2011. Approximately 84% and 86% of royalty revenue for 2010 and 2009, respectively, was derived from this contract. The receivable from this search engine provider represented 64% and 71% of the December 31, 2010 and 2009 outstanding receivables, respectively."

Doing the math, that's about $10.2 million delivered to Mozilla last year. Conventional wisdom based on last year's numbers say Google will have delivered about 1.06 trillion (with a "t") searches worldwide this year. That makes Firefox responsible, based on Chitika, Inc.'s estimate of Firefox's delivery power, for nearly 97 billion Google searches worldwide. For every dollar spent, that's 9,504 searches - which by any standard is a bargain.

The math says it's more sensible to feed the hand than to bite it.