As Apple has increased rejections of emerging apps that may (directly or indirectly) conflict with its business interests, many of these apps find their way into the market by avoiding the iTunes store.
Much controversy has surrounded some of these rejections by Apple. Perhaps one of the most notably conversial rejections was the Google Voice app, which will now be available to iPhone users via a web browser since the request for distributing the application via iTunes was rejected. Many application developers are not taking such rejection as a final answer. Some of these apps quickly become available via the Jail-breaked/hacked app store called Cydia. Cydia is essentially the blackmarket for applications not allowed into the regular markets. The Cydia app store is both a free package repository and commercial storefront to third-party developers.