There are some apps for Android and other platforms that offer voice calling and SMS services through Google Voice. There is currently no official API for Google Voice. These third party apps are therefore getting unauthorised access to Google Voice services.
Google announced that these apps have six months, that is till May 15th 2014 to live. Then they will be ousted from Google Play and hence from all Android devices. Google says these apps violate its terms and conditions and pose a security threats to users, although it is still unclear how. One of those apps is GrooveIP, which many people use around the world. Read more