In cleaning out my inbox, post-MWC, I came across a report released earlier this month from research firm Distimo. The report finds that the two fastest-growing mobile application stores are now the Google Android Market and Microsoft's Windows Phone 7 Marketplace. Android's app store had a growth rate of 18% during the month of January 2011 while the WP7 Marketplace grew at a rate of 30%.

In Microsoft's store, more paid applications than free apps arrived (1,027 and 576 apps added, respectively) while in Android's Market, that trend was reversed (16,150 free apps added compared with 6,847 paid apps).

You can see this growth on the chart below:

Of course, this is growth only, not total number of apps. The iPhone clearly has everyone beat on that metric. It's interesting, however, to see that the iPhone's App Store only grew by 1% during January. Has it reached a saturation point? Are developers devoting their resources to launch on competing platforms now instead of creating more iPhone apps?

Regional Overlap

But trends surrounding app growth and related pricing weren't the only things Distimo examined this month - it also looked at regional distribution and top publishers.

Windows Phone 7, however, shows a much more localized picture - countries have an overlap of between 44% and 69%. What this means, Distimo explains, is that users on Windows Phone 7 devices will have an easier time finding localized content than Android users.

Multi-Store Distribution Trends

Distimo also looked at the distribution of apps across multiple app stores (iTunes, Android, Ovi, etc.). Here, the firm found that out of the 200 most popular applications that are available in at least 2 different stores, 147 publishers have at least one app in the Android Market. Meanwhile, only 57 of the top 200 publishers have an app on Windows Phone 7.

Although this figure is lower than Android's, it isn't significantly lower than other app stores that have been around for longer, says Distimo. In the chart, you can see that the Windows Phone 7 app store rivals Palm's App Catalog and isn't too far behind Nokia's Ovi Store.

More details on top publishers (free and paid, apps vs. games) is found in the 25-page report available on Distimo's website here.