What is Facebook Platform?
You've always had applications (things like Photos, Notes, and Events), now you have more to choose from. This is because we've launched Facebook Platform, which enables anyone to build any application that we here at Facebook could build.
Now when you get to a friend's profile, things have the potential to look different:

Add more Applications
Amy here chose to add Video, a new application built on Platform.
Amy here chose to add Video, a new application built on Platform.
More control over your profile
In this example, Amy moved her Photos to the wide column under her mini-feed.
In this example, Amy moved her Photos to the wide column under her mini-feed.
Find new applications from the Application Directory, or in your friends' profiles:

Whenever you see an application that you might want on your profile, look for the link to "add" it.
You will be taken to a page where you can confirm that you want to add that application. If you choose to add it, you will be redirected to a page where you can start using the application.

You can rearrange your profile at any time.
Simply hover your mouse over the application's title bar, then drag and drop the box where you want it to go. This works for all Facebook applications, including Photos, Notes, etc.

Easy Removal
When you want to remove an application, change privacy settings, or manage any of your applications, simply go to the Edit Applications page.
You can rearrange the order of applications in your left-menu when you're in edit mode.