The Twitter C# SDK by linvi (aka Tweetinvi) allows developers to integrate the Twitter API into their C# / .Net applications. This SDK can be used to develop for Windows, Windows RT, Windows Phone, Mono, and Xamarin Android / iOS.
ProgrammableWeb has been tracking Twitter mashups since the first one was added in December, 2006. Looking at the number developers have added to the database, one thing is clear: 2009 was a huge year for Twitter and apps built upon it.
Google this week released a new API for Friend Connect (our new Friend Connect API Profile), its relatively new service that enables social networking features to be easily added to any existing web site (utilizing copy and paste code that leverages OpenID, OAuth, and OpenSocial). The API allows developers to tap into some of the core features of Friend Connect.