With Instagram's new App update, the "find your friends" on Twitter is very obviously missing. This is due to restrictions from Twitter's side, and seems to be a snub in Instagram's direction as many apps like Foursquare still have access to this part of the API.
The web's largest video site has added a new personalization feature to its YouTube API. Sure to be misunderstood as a privacy concern, the service now lets applications access viewing history for authenticated users. Amazon also made two announcements related to its storage and database services. That and 19 new APIs round out today in APIs.