Chrome is within striking distance of Firefox for second place in worldwide browser usage, but that hasn't stopped Google from throwing its financial weight behind the non-profit browser. (Credit: Net Applications) Don't let the StatCounters and the NetApplications of the world fool you: despite stagnant and even slightly negative market share growth, Firefox andits default search box is still extremely valuable to Google. How valuable? The three-year default search deal that Firefox's nonprofit parent company, Mozilla, just inked with Google isworth nearly $300 million per year, according to unnamed sources who spoke to AllThingsD . In a statement to AllThingsD, Google's senior vice president of search, Alan Eustace, said: "Mozilla has been a valuable partner to Google over the years and we look forward to continuing this great partnership in the years to come." To those who spend a lot of time observing Mozilla, the deal is no surprise . Mozilla revealed in October that Google contributed the vast majority of its revenue for fiscal year 2010, around 84 percent. That figure came in at $123 million, an 18 percent jump over 2009. Thenew deal, at nearly $300 million per year, would represent around a 40 percent jumpfor Mozilla, which has aligned itself with defending openness on the Web. Openness doesn't mean a lack of business acumen, apparently. According to the report, Mozilla was entertaining offers from both Microsoft's Bing search engine and Yahoo. Even though Yahoo search is powered by Microsoft, landing the Firefox default search slot would've been seen as a way to staunch Yahoo's declining marketshare. Yahoo determined the deal to be"too costly," but Mozilla still has partner deals with other search providers such as Amazon, eBay, Yandex, as well as Bing andYahoo. Double the money may make things easierfor Mozilla, but the company still has a challenging road to tread. Chrome is the still-rising star of the browser world, Internet Explorer 9 and the nascent version 10 continue to grow beyond techiepunchline status, and the even with this week's release of Firefox 9 for PCs and Android , Mozilla struggles to redefine its mission against the backdrop of a rapidly changing Web . Seth Rosenblatt Seth peers into the deep, dark corners of software so that you don't have to, including browsers and security on Windows, Mac, and Android. He has yet to suffer a single nightmare about OS/2, although let's face it: there are far scarier things out there besides long-dead operating systems. For instance, take the rumored Angry Birds/FarmVille crossover app...