Google Voice (formerly GrandCentral) is a telecommunications service by Google launched on March 11, 2009. Google Voice had some 1.4 million users in October 2009, 570,000 of whom used the service 7 days a week. This number has risen since Google transitioned its Google Voice service from 'invite only' and made it available to all Gmail subscribers, but Google has not released a more recent number of users, claiming only that it is in the millions.
The service is configured and maintained by the user in a web-based application, styled after Google's e-mail service, Gmail, or through the service's Android and iOS apps. Google Voice currently provides free PC-to-Phone calling and PC-to-PC voice and video calling worldwide between users of the Google Voice and Video Chat browser plugin (available for Windows, Intel-based Mac OS X, and Linux).
Users resident in the US may place outbound calls to domestic and international destinations from their cell phone app, from the web-based application, or by dialing their Google Voice number. As of August 2011, users in many other countries also may place outbound calls from the web-based application to domestic and international phone numbers. Domestic and outbound calls to the US (including Alaska and Hawaii) and Canada are currently free from the U.S. & Canada and $0.01 per minute from everywhere else. International calls are billed according to a schedule posted on the Google Voice website. For incoming calls, users must have an established US telephone service to activate their own Google Voice phone number. Users must configure this and/or additional phone numbers that ring simultaneously when their Google Voice number receives a call. The user may answer and receive the call on any of the ringing phones or through the web-based app. The service provides a US phone number, chosen by the user from available numbers in selected area codes, free of charge to each user account. Inbound calls to this number are forwarded to other phone numbers of the subscriber. Received calls may be moved between configured telephones during a call.
Many other Google Voice services—such as voicemail, free text messaging, call history, conference calling, call screening, blocking of unwanted calls, and voice transcription to text of voicemail messages—are also available to users resident in the US. In terms of product integration, transcribed and audio voicemails, missed call notifications, and/or text messages can optionally be forwarded to an email account of the user's choice. Additionally, text messages can be sent and received via the familiar email or IM interface by reading and writing text messages in Gmail or by adding contact's phone numbers in Google Talk respectively (PC-to-Phone texting).