From Social Patterns

the facebook UI has the prompt 'What are you doing right now?' inside of the status message input box.

Positives: It asks a question

   + it is grey so you might know that you type something in there.

Negatives: The box where you type things in is weird to have a question already inside it. Breaks the normal label/prompt vs. input area pattern

  - & when you touch it, it becomes <UserName> 'is ' which gives you more hints but also violates the 'get focus' shouldn't change things to much pattern
  + this is oriented for ease of recurring use, shorthand, etc. - balancing first time users & facebook active users is potentially challenging.

=trn