Google Blog: “Many third-party apps, services and websites build on top of our various services to improve everyone’s phones, working life, and online experience. We strongly support this active ecosystem. But increasingly, its success depends on users knowing that their data is secure, and on developers having clear rules of the road. Over the years we’ve continually strengthened our controls and policies in response to regular internal reviews, user feedback and evolving expectations about data privacy and security. At the beginning of this year, we started an effort called Project Strobe—a root-and-branch review of third-party developer access to Google account and Android device data and of our philosophy around apps’ data access. This project looked at the operation of our privacy controls, platforms where users were not engaging with our APIs because of concerns around data privacy, areas where developers may have been granted overly broad access, and other areas in which our policies should be tightened.   We’re announcing the first four findings and actions from this review today.

• Finding 1: There are significant challenges in creating and maintaining a successful Google+ product that meets consumers’ expectations.
• Action 1: We are shutting down Google+ for consumers…”

See also the Washington Post – Google for months kept secret a bug that imperiled the personal data of Google+ users
NBC News – Google says it found security flaw in March but chose not to tell users