The SugarSync Java SDK by Heliocentric communicates with the API to access syncing data. With the kit and the API, developers could integrate file sharing and backup features into web services and mobile applications.
Just about every provider of a platform in the cloud is moving down the same path; albeit at different rates of speed. First they figure out that developers of third-party applications can drive more usage of their platform, so they publish a private API. However, it’s not too long before they figure out that making that API public winds up driving the most usage of their platform.