Facebook's instant messaging service, which is available on the Facebook website and as an app for mobile devices. Introduced in 2011, and initially bundled into the Facebook mobile apps, instant messaging was separated into the stand-alone Messenger app in 2014. In addition, iPhone and Android users can use Messenger as their primary text messaging client (SMS) and not have to switch between apps for messages from non-Messenger users.As of 2019, Facebook Messenger and Facebook's WhatsApp instant messaging exist as separate services, each with more than a billion users. See Chat Head, WhatsApp Messenger, Facebook M and Facebook.Messenger Kids With Parental ControlsIn 2017, Messenger Kids was introduced for children under the age of 13. Parents have to authorize its use and are in control of whom their children can text and chat with. Digital stickers and animated masks let kids create fun photos and videos.