Mobile advertising firm Millennial Media has just released its comprehensive report on the state of the mobile application industry, which includes a look at growth trends, platform diversification, platform popularity, 2011 trends and more.

According to the report's findings, developers plan to further diversify their app offerings next year and - here's some good news! - they expect to see "significant growth" in app revenue over the course of 2011.

UPDATED DATA, please see below.

This Year's Popular Platforms

In terms of popularity, Millennial found that the iPhone is still the platform of choice for mobile developers, but others, including Android, iPad, Windows Mobile and Symbian saw big increases over last year as developers began launching their non-iPhone apps in attempts at diversification.

The current top five platforms in 2010 were iPhone (30%), Android (23%), iPad (21%), RIM (12%) and Windows Mobile (6%).

Next Year's Popular Platforms

This trend of diversification will continue in 2011, says Millennial, with the iPad, Android and Windows Phone 7 all picking up steam over the coming months.

The report found that 29% of developers will target Android in 2011, while 20% will target iPad and 20% will target Windows Phone.

Seeing Windows Phone 7 make the list of up-and-comers may be a little surprising, but it speaks well for the platform's future, mainly due Microsoft's (apparently successful) efforts to generate developer interest in its new mobile operating system and its fairly positive reception among technology reviewers and enthusiasts.

Revenue Trends for 2011

Publishers were also asked to estimate their 2011 revenue. for the study Based on the answers given, it's almost universally good news. 31% of publishers expect their revenue to increase by 100% or more, 17% say they expect a greater than 50% increase and 6% expect a greater than 25% increase. Only 10% of developers expect revenue to stay flat.

The study, which was performed by DIGIDAY and analyst Jordan Rohan of Stifel Nicolaus in conjunction with Millennial Media, asked 500 developers, advertisers and publishers about their future mobile plans. The full report is available as free download from Millennial Media's website, if you provide your email address.

UPDATE: We noticed a discrepancy between two sections of the report and asked Millennial for clarification. There was an error in their report which reflected on the projected revenue numbers. Originally, they reported 2% of developers said revenue will remain flat in 2011. That has been changed to 10%. This affected other numbers as well. The actual numbers are as follows:

Publishers' Expected Increase in Apps Revenue from 2010 to 2011:

  • 100% increase or more: 31% (same)
  • >50 increase: 17% (same)
  • >25% increase: 6% (not 17%)
  • 10-25% increase: 17% (same)
  • 5-10% increase: 17% (not 10%)
  • 1-5% increase: 0% (same - in key, but doesn't show up on chart)
  • <1% increase: 2% (not 6%)
  • Flat: 10% (not 2%)

We have replaced the old chart with the new one reflecting these changes.