How do you make it so that a question you edit or answer never goes on your Watchlist?
Click the "My settings" in the left-blue pod and then uncheck the "Add pages you edit to your Watchlist by default." checkbox.
If you are the first answerer, your name goes at the bottom of the page as the "First answerer." If you are the last entry here, your username goes down there as the "Last edit." If you answer in the middle, your name will still be in the history, but it won't be listed at the bottom. Your answer will still be there; it's never lost, just in the data base.