Each day, for the next ten days, Google will be celebrating 10 billion downloads from the market with 10 apps each day, each being offered for 10 cents each.
Android Market Promo Page
Google Blog
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One billion is a pretty big number by any measurement. However, when it’s describing the speed at which something is growing, it’s simply amazing. This past weekend, thanks to Android users around the world, Android Market exceeded 10 billion app downloads—with a growth rate of one billion app downloads per month. We can’t wait to see where this accelerating growth takes us in 2012.
Android Market Promo Page
Google Blog