As a Supervisor, my favorite WikiAnswers feature (though not available to regular contributors) would have to be the Batch Revert feature.
The Batch Revert feature is a tool that allows Supervisors undo vandalism in answers caused by a single contributor (registered or not registered) in less than a minute. This feature can do anywhere from 1 to 1000 reverts at one time, so it is a definite favorite in combating vandal attacks.
A profile page
No, WikiAnswers does not have that feature.
Wikianswers
Yes there is a forum on WikiAnswers. You can access it from the Related Links or on the blue sidebar on the left.
Yes, if you are a supervisor.
My favorite rabbit is the "you're flooding wikianswers with stupid questions" rabbit.
You type your favorite music station on wikianswers.
My favorite feature of the Assistant is its ability to provide quick and accurate information on a wide range of topics.
If you mean your Discussion board then you can find it under MyPages which is on the left side of the screen on the Blue Navigation bar. But, if you mean the WikiAnswers Email, which, you have to be a supervisor to have that feature and get an WikiAnswers Email.
The "Unwatch" feature is used to unsubscribe a question from your watchlist.
There is no way for WikiAnswers to look at a diagram you are seeing.
It depends on your point of view. Everyone has different views, so the coolest thing about WikiAnswers is your favorite subject.
WikiAnswers email accounts are only given to WikiAnswers Supervisors. There is the message board feature on WikiAnswers that you can use to message other users. Simply click on 'Message This User' on the top right of a users bio page to add a message.