'Facebook Phone' in the works with the help of Taiwan-based HTC
The Next Web

Rumors of an upcoming Facebook phone have been around for quite some time now. A new report now reaffirms and even adds a few new details to the same, sparking speculation that this particular smartphone's launch could be closer than most people anticipate. Apparently, the so-called Facebook phone's working codename is simply "Buffy," and it will be built with the use of the Android operating system. Apart from what's written above, there isn't really any information available on the Facebook phone. And there's hardly any real evidence for it either. Still, a lot of people eagerly await its release to be able to fully enjoy a more integrated Facebook experience.

What Else You Need To Know:

- It is said that the Android-powered Facebook phone will be released some time in early 2013.

- HTC has always been the manufacturer named as the future Facebook phone's maker ever since the earliest rumors began to spread.

- Many people strongly believe that having its own phone would greatly help Facebook get a grip on its overall strategy for mobile.

Other sources

Some think that having its own phone would be a bad idea for Facebook, but I truly believe that it would be targeted at a younger audience and could definitely solve some of the mobile issues that it has experienced. - Drew Olanoff, The Next Web  
The Next Web
Facebook is working with HTC on a mobile phone for 2013 release, reports Bloomberg
iPhone Download Blog
Facebook phone reportedly set for 2013 release
Facebook and HTC reportedly prepping a smartphone that could debut in mid-2013
Android Community
HTC rumored to make another ‘Facebook Phone’ in 2013
HTC Giving The Facebook Phone Another Go? Coming 2013 [Rumors]
Android Guys
Facebook working with HTC on a new device, launch in 2013?