When you are signed in to social networking services through the Social application, you can see your friends' status updates from all those services in a single view. You do not have to switch between different applications to see what everyone is up to.
Select Menu > Applications > Social.
Select a service, and sign in.
Select Add social network.
Select another service, and sign in.
Select All Activity.
All the feeds from the services you have added are automatically included in the view.