Windows Phone 7 has tight integration with social networks especially Facebook and it automatically adds all your Facebook contacts in your address book. Now there are two more apps released for Windows Phone 7 based on Facebook- Facebook Places and Facebook Messages. Check In provides the same functionality of Facebook check in for Windows Phone 7.

Another app which has been added for Windows Phone 7 is Facebook Instant Messenger (FIM), which provide you with option to chat with your Facebook friends right inside Windows Phone 7.