The company behind Cydia, an iPhone app store that launched before Apple's own App Store, has sued Apple arguing that Apple has monopolized the market for iOS app stores, violating antitrust law in the process.

When the iPhone was introduced in 2007, it didn't have any mechanism for natively running third-party software. Instead, Steve Jobs encouraged developers to create Web apps that would run in the iPhone's Safari browser.

But people soon figured out how to jailbreak the iPhone and began making iPhone apps without Apple's help. Seeing an opportunity, software developer Jay Freeman created a program called Cydia that made it easy for users to download and install native iPhone apps—an app store before the App Store.