The Tweetinvi C#/.NET library provides access to the Twitter REST and Streaming APIs. This unofficial library offers 3 different classes for Messages, Twitter Users, and Tweets. Tweetinvi also offers Streaminvi, for access to the Twitter Streaming API. The Streaminvi library has two classes, SimpleStream for all the data provided by Twitter, and FilteredStream for extracting specific data from Twitter. The Tweetinvi library is offered under a Microsoft Public License (Ms-PL).
As announced earlier this year, Google officially retired the Hangouts API. As Hangouts is repositioned for enterprise use, the need for some of the social, consumer focused video features of the API are no longer a priority. Accordingly, the end of the API was first announced and now realized.
When Nate Drouin, the founder and CEO of Fundraise.com, first sat down with Dustin Dulginow of Atlas Venture he had already finished development of the Fundraise.com Iphone/Ipad applications (the Fundraise.com API came later). That lunch meeting must have gone well because Atlas Venture later became one of the investors that contributed to a $1.2 million round of seed money for the startup.