Mozilla’s Firefox web browser reached the 1 billion downloads mark on July 31st, 2009.

OneBillionPlusYou.com, a site created by Mozilla to celebrate the achievement, asks the big question: “How Much is One Billion?”

Some of their answers include, “[a] bowl big enough to fit one billion goldfish would be as big as a stadium,” and “[o]ne billion stacked coins would reach nearly 1,000 miles high.”

The milestone includes browser downloads and user initiated updates since Firefox 1.0 was launched in 2004. Automatic updates were not included in the figure. Consequently the figure doesn’t mean that there are a billion Firefox users, but rather that Firefox holds somewhere close to 30% of the web browser market globally; a figure closer to 300 million users.

Follow the number of Firefox downloads here.