Now that Apple's App Store and Google's Android Market have over half a million applications combined, it seems obvious that apps are a huge deal for both customers and developers.  A new projection from Citibank claims that apps will be even bigger next year, as they estimate that the App Store alone will bring in $2 billion in revenue in 2011, despite their belief that overall smartphone sales will grow only 29 percent.  Research firm Gartner is expecting even higher profits, projecting that global app sales revenue reached $4 billion in 2010 and will grow to $27 billion over the next two years. 

Considering that the App Store has anywhere between 300,000 and 400,000 apps available and that Apple will be launching the iPad 2, iPhone 5, and likely a Verizon iPhone next year, it's no surprise that Citibank thinks that the revenue from Apple's app shop is going to be a cash cow.  I'm sure that the Android Market is going to rake in a decent amount of money, too, with its ever-growing selection of apps and devices to use them on.  Plus, the App World, App Catalog, Windows 7 Marketplace, and Ovi Store will all contribute to sales over the next couple of years.  That $27 billion revenue estimate doesn't sound terribly crazy, huh?

Via BGR, TechCrunch