Normally you might consider the usual places to see Firefox mentioned: Slashdot, The Register, etc. Interesting to note that as Firefox adoption continues to grow, there are more "mainstream" references being tossed about. For instance, a very popular news station in Philadelpha, KYW 1060 has been running promo spots on how their webcasting now works with Firefox.
What could this mean? I'm not too sure it represents anything other than the public's new willingness to try new browsers. Although Microsoft used Internet Explorer to win the so-called "browser wars", as to exactly how that enforced operating system sales remains to be proven! Other than extremely difficult-to-quantify measures of success like "mindshare" and "lock-in", nobody has ever explained concisely and clearly how MS really made more money from their browser.
MS is coming out with Internet Explorer 7, featuring tabbed browsing. They are finally advancing their browser design to keep up with the jones', and I'm sure that will make them look better as a company and every bit helps. But with their marketshare on the desktop so strong, how much growth they can pull off remains to be seen. This is probably why they are expanding into search, game consoles, smart phones, etc- to create company growth.
As a matter of fact I'm pretty impressed with their search offering. It will give Google some competition, hopefully driving technological innovation in the search market more effectively than Google hiring as many PhDs as they can find. But there are rumors and speculation that Google now wants to be MS, in light of how they may use the Firefox browser to make some kind of G-Browser, and create a web-based OS. Or maybe they just want to be a portal for now, as recent changes have shown.