The Firefox 4 web browser has proven to be a big hit for Mozilla. At the time of this writing, 52,204,769 people have downloaded Firefox 4.

Europe has the highest number of users with 20,365,540. North America has 16,688,275, and Asia has 9,247,750. Obviously these numbers will be slightly off, considering the downloads are rolling in faster that it takes me to type a single character, but you get the idea of what the markets are like.

At glow.mozilla.org, you can watch the number continue to tick upwards and get a market-by-market breakdown of the numbers.

It had already hit 9 million downloads just a day after it launched. This infographic showed how well it did in its first 48 hours alone:

It’s hardly slowed down since then.

Earlier this week, Mozilla launched Firefox 4 for Android to mixed reviews. Complaints were mostly related to speed and a lack of Flash support.

Read reviews (of the desktop version) from a couple of our writers at the following links:

Firefox 4 Review: Many Likes, Few Dislikes
Firefox 4 Official Release – Was it Worth the Wait

In other browser news, IE9 has an adoption rate five times higher than that of IE8. Rockmelt launched its Beta 2 today with new Facebook Chat and real-time Twitter features.