First up is push notifications. With this new feature enabled, iPhone users will be alerted when they receive Facebook messages, and other missives or interactions with their friends. This will let iPhone users experience a more real-time effect with their social network.
The second -- and in my opinion, more useful -- new feature is the ability to sync Facebook contacts data with the iPhone's native address book.
Palm's webOS and Motorola's MOTOBLUR already offer this feature, which makes interacting with your contacts database a lot more enjoyable. When enabled on the iPhone, users will first have to agree to the following terms of service:
Does Facebook really expect anyone to get the OK from their friends before enabling this feature? I highly doubt it.
If you enable this feature, contacts from your device will be sent to Facebook and your friends' names, photos, and other information from Facebook will be added to your iPhone address book. Please make sure your friends are comfortable with any use you make of their information.
The updating process was a bit lengthy, but once completed, had added profile pictures and other information from my Facebook contacts to my iPhone. This is something I've wanted to some time now, and am glad that Facebook finally enabled the feature.