I would like to note that FB on Android and iOS are made by Facebook. The ones that do exist on Android not made by FB, are pretty bad themselves and I see plenty of bad reviews for the FB app in general, even the one they made. Sorry getting side tracked, my point is that it is not Microsoft's fault that FB has not came out with an app for the Windows Phone.
So to make a long story short, this is the exact same thing we dealt with in regards to the first smart phones. When IPhone came out it has a pretty good app listing, but no where close to what we have today. When droid came out, everyone talked it down because their were not very many apps and compared it to the iPhone. Now look, Droid has over 700,000 apps! that is incredible and so will the Windows Phone. The adoption rate has been slow and many app designers have not seen a market yet, but I believe when droid users start to test these things out and relize how great they are, we will see many new apps coming to market.
Also Microsoft appears to have made it very easy to develop apps for the windows phone, even someone who has never done it before should be able to jump right in and create something pretty basic. Anyhow if you want your favorite apps on the Windows phone, hit up those company's and stop blaming Microsoft. If you compare Microsoft's solutions to its competitors, you will see Microsoft actually makes their applications much easier to access on other devices. Example: SkyDrive Microsoft's solution to cloud storage. This application is designed to work on Windows devices, Mac Devices and Droids. Microsoft does a lot to make sure their solutions work seamlessly with all other devices, we cannot say the same for others.
So if you have an issue with an app not being available on a specific device, contact the vendor and stop blaming Microsoft its getting old. OR how about everyone who likes to complain about not having specific apps, develop their own? You have access to the ADK..
Sorry about the rant, but someone had to say it.
-RD