A couple of updates have appeared for my Nexus One on Android Market today, among which are Facebook and Twitter. For the latter, the updates bring speed, a cleaner timeline, tweet details and Pull to refresh.
Facebook app for Android seems to bring some more features.
1. Groups: It is now possible to share posts with just a small group of friends.
2. Places: Share where you are with friends, see where friends are and discover nearby places.
3. Improved Notifications: View comments and updates within the app.
The forth item is the usual "various bug fixes".