While everyone is app happy these days, two pieces of new data point to the important role that both iOS and Facebook are playing in the app marketplace.  

Facebook, which began rolling out its previously announced App Center last week, is already playing an important role in app discovery and reportedly drove people to the Apple App Store 83 million times in May. In another piece of data, Flurry Analytics reported that seven out of 10 apps built are for iOS.

"These are not big numbers [for Facebook]," said Simon Khalaf, president and CEO of Flurry Analytics, San Francisco.

"As a point of comparison, Flurry AppCircle has sent 128 million users to the appstore and has driven 670 million sessions which is equivalent to the clicks that Facebook is talking about," he said. "But that means that there is a good opportunity for Facebook to even do a better job and help the ecosystem."

"Facebook does not appear to be making money from these apps. This move appears to be about having reach and relevance into the mobile app world, not about driving revenue in the short-term."

Social apps
The Facebook App Center began rolling out to people in the U.S. on June with more than 600 apps and is the latest example of how Facebook is trying to boost its mobile offerings.

At launch, the App Center features mobile and web apps, such as Draw Something and Pinterest. It also lets users browse the apps their friends use and provides personalized recommendations.

The mobile integration includes making the App Center available in the Facebook iOS and Android apps. Users can also send apps they find on their computer to their mobile device using the ?Send to Mobile? feature.

Facebook also reported that seven of the top 10 grossing iOS apps and six of the top 10 Android apps had integrated with Facebook as of May.

The news comes at a time when both Apple and Google are preparing for their annual developer conferences. The Apple Worldwide Developer Conference starts today in San Francisco while Google?s I/O conference kicks off on June 27, also in San Francisco.

Attracting developers is key for mobile operating platforms because consumers are hungry for apps and having a robust app offering is key to attracting more consumers and this, in turn, will attract more developers.

Apple has been the clear leader in terms of apps for a while, with developers choosing to invest their budgets in iOS apps first. However, Facebook is also clearly beginning to play a bigger role in app discovery, driving integrations with iOS and Android.

Flurry?s analytics show that Apple continues to gain further support from developers, with iOS having a 69 percent share of new project starts in apps for the first quarter of 2012 while Android had a 31 percent share.

Google?s share was slightly above where it was in the previous quarter and iOS? slightly below. However, Flurry believes this is because of a spike in developer support experienced by Apple in the previous quarter.

Attracting developers
A key point of differentiation between iOS and Android for developers is how much more money they are likely to generate on the former. Flurry?s data shows that for every $1 a developer earns on iOS, it will earn about $0.24 on Android.

Another reason why iOS is attractive to developers is Apple?s dominance in the tablet category, according to Flurry. This enables developers to leverage both the iPhone?s large user base while building for the iPad at the same time. 

According to Flurry?s data, the iPad commanded 88 percent of worldwide user sessions between January and March of this year while the Samsung Galaxy Tab had a 9 percent share and the Kindle Fire 3 percent.

While iOS offers developers a compelling proposition, the fragmentation of the Android ecosystem drives complexity and costs for developers.

The Samsung Galaxy S II had an 18 percent share of worldwide app user sessions in May, the largest share of the top 20 Android devices tracked by Flurry.

However, all the others had shares less than 10 percent. This means that each additional device a developer supports will deliver only a small increase in distribution coverage.

Flurry?s data also shows that the majority of consumers are running on an Android operating system that is three to four iterations old.

"Based on Flurry data, it is clear that iOS should be the lead platform for developers," Mr. Khalaf said.

"Developers can't ignore Android, so that should be their second platform," he said. 

"Developers also should integrate Facebook's Open Graph to have access to its single sign-on feature and get a bump in free, organic traffic from Facebook."