MKAbeFook for Facebook. Uses the WebKit browser with asynchronous requests, photo uploads, and much more. It can call any API method and returns the result in standard Cocoa types. It is distributed under a BSD style license.
Are you a developer who wants to get your news immediately? The New York Times NewsWire API, which provides links and metadata for Times articles the moment they are published, might solve your problem. But what if your news alert mashup doesn't quite get every bit of your undivided attention? Jer Thorp's NewsAlarm (our Mashup of the Day), combines the NewsWire API and an 85 decibel smoke detector into what might be the loudest mashup on the planet.
Perhaps your most important online network of business contacts is now programmable. LinkedIn launched its API (our LinkedIn API profile), which allows developers to access a user's connections and anyone's profile data, in addition to several other features. Though some are saying "finally," it's clearly not too late for LinkedIn, who aims to be the professional networking platform.