The Twitter Kit for iOS, supported by Twitter as part of the Fabric developer suite, helps developers create iOS applications that integrate various Twitter functionalities. The SDK can be used to implement easy Twitter login, composing tweets, displaying tweets, and authentication all from a 3rd party application. The iOS Twitter Kit includes "Login" for standard login, "Twitter API," for iOS driven API requests, "Tweet Views," for displaying a user's Twitter stream, "Tweet Compose," for composing and posting new tweets, and "Digits," a new way that users can verify with Twitter via their mobile phone number over SMS-based authentication.
Wishpot typically brings "lists" to mind. With Wishpot's original service, users could create a single wish list from multiple sites. The service eliminated the need for a new list for every site in which a shopper was interested. Wishpot has now expanded the wish list experience into a full shopping experience with a new API framework that provides true social commerce (shopping/browsing through checkout from the same platform).
For the developer seeking to experiment efficiently with social APIs, O'Reilly's 2nd Edition of "Mining the Social Web" is a truly outstanding resource.
Author Matthew A. Russell drops the developer right into the sandbox of each social network (Twitter, Facebook, LinkedIn and Google+ are particularly emphasized, as you would expect) with just the right amount of explanation about what's accessible via each dataset, and then clears out all the obstacles so they can start data mining against very clear examples.