Apple is considering LinkedIn integration for iOS 7, beta code references suggest. In particular the references hint that LinkedIn could be supported in the same manner as Facebook and Twitter, meaning single sign-in support, and the ability to quickly post content via a share sheet or hooks in iOS apps. Some essential code strings are missing though, preventing LinkedIn options from turning on in the current iOS 7 release.
could turned on in later betas or in time for the finished iOS 7 release. LinkedIn support may be likely, since integration has already been announced for OS X Mavericks. iOS 7 is also gaining Vimeo, Flickr, and Tencent Weibo integration, which makes LinkedIn a minor addition by comparison.