updated 12:34 pm EDT, Fri April 12, 2013
Messaging system from Facebook Home included without launcher
Facebook has rolled out part of its upcoming Facebook Home launcher in an Android app update, before the company released its new phone software initiative. Facebook Messenger (Google Play) now has the option to enable the Chat Heads pop-up contacts onto phones and tablets, without the need to install the complete Facebook Home suite itself.
Incoming messages will cause a Chat Head for a contact to appear on the side of the screen, if enabled within Facebook Messenger. Facebook conversations and SMS messages will work through the app, which also appears to work on devices other than the ones due to receive Facebook Home later today.
The main Facebook (Google Play) app itself also received an update on Android, with an option in the menu to "Enable Facebook Home." At the time of writing, selecting the option opens the Google Play store, but fails to load a product listing.