It is reported that the device they are working on is named "Buffy", taken the name of the vampire slayer TV series, played by Sarah Michelle Gellar. And it will use an Android's modified version as its operating system.
And likely we will be seeing Facebook's service integration with HTML 5 support in this modified version.
However Buffy is not a pioneer smartphone that is set with deep integration of Facebook service. Giant technology companies like Motoroal, Inq Mobile and HTC have preceded it with dedicated FB features bundled.
Let me know your thoughts about this upcoming Facebook smartphone codenamed Buffy.