“Google has announced that they are closing the consumer functionality of Google+ due lack of adoption and an API bug that leaked the personal information of up to 500,000 Google+ accounts. While no evidence was found that indicates this bug was ever misused, it was determined that the complexity of protecting and operating a social network like Google+ was not a worthwhile endeavor when so few users actually used the service for any length of time. ‘This review crystallized what we’ve known for a while: that while our engineering teams have put a lot of effort and dedication into building Google+ over the years, it has not achieved broad consumer or developer adoption, and has seen limited user interaction with apps,’ stated a blog post by Google regarding the Google+ closure. ‘The consumer version of Google+ currently has low usage and engagement: 90 percent of Google+ user sessions are less than five seconds.'”
Source: Google+ Shutting Down After Bug Leaks Info of 500k Accounts