When you take a look at Net Applications' web desktop browser market share reports over the long run two things stand out. One, there's the rise of Google's Chrome to second place, and two, Mozilla's Firefox's steep decline.

How bad is Firefox's fall? In June 2014, Firefox hit a new five-year low of 15.6 percent market share.

Back in October 2009, Firefox was on the rise and had reached 23.75 percent . Life was good. Since July 2012, the browser started trending downward. Indeed, since May 2013, with Firefox at 20.6%, the once popular browser hasn't risen above 20%.

As for the other desktop web browsers, Internet Explorer (IE) retains first place with a new two-year high of 58.4 percent in June 2014. Chrome, which jumped from 17.7 to 19.3 percent between May and June 2014, gained the most from Firefox's decline. Apple's Safari has also not been doing well. At 5.3 percent, Safari hasn't been this unpopular since March 2013.

Why is that happening? That's a good question.

Certainly the improvements and publicity for Chrome and IE hasn't hurt any. Firefox's reputation, on the other hand, has been tarnished by adding ads to the web browser and by Mozilla's continuing CEO problems .

Adding to the problems is the fact that Mozilla's ad deal with Google is coming to its renewal date . This is significant because over 90 percent of Mozilla's revenue comes from Google but Google now has its own browser. It's hard to see Google renewing the deal.

While Mozilla has hopes to become a mobile operating power with Firefox OS , it's made little progress against the two mobile operating system giants: Google with Android and Apple with iOS. Even if Mozilla were to do better than its management's wildest dreams, it's hard to see Firefox OS licensing fees making up for its potential Google revenue losses.

Speaking of mobile, the Firefox browser is a total non-player in this market. As of June 2014, Safari had a 46.1 percent share of the market; this is followed by the native Android browser with 22.8 percent; Chrome with 16.7 percent; Opera Mini at 7.6 percent, Internet Explorer at 2 percent; and, finally, almost lost in the noisem is Firefox at 0.7 percent.

For Firefox to remain a web browser power, it needs to make big improvements and it needs to make them now. Otherwise, Firefox may yet follow its predecessor Netscape into the web's past.

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