On the first day of MIX 2010, Microsoft released a number of software development toolkits for Windows Phone 7 application developers to use, including a Silverlight 4 multimedia toolkit, for developing Rich Internet Applications (RIA), and a beta release of Microsoft Expression Blend 4, a GUI-designed and code-generating toolkit. The tools will run inside Windows PC Visual Studio 2010. Microsoft demonstrated a number of applications that had already been created to run on Windows Phone 7, including a news reader app from the Associated Press and an app called Seesmic for managing Twitter accounts and feeds.