There should be some way for the user to know/check if the question he is about to post already exists.
Just for an example,suppose the user types a sentence containing the word 'getInitParameter()' ,then all the previous related questions should be loaded somewhere near the subject box.I mean what i am saying is similar to google search,when you type a word,Google loads the related as you are typing.
That would kind of be a good idea!! what say??
But surely you have read HowToAskQuestionsOnJavaRanch and SearchFirst in particular, so you will already know whether or not there are any questions similar to your own, so there's no need for this feature.