The question: Do you find stackoverflow useful in your daily development work ? Do you want to actively contribute to keep stackoverflow's content top-notch ? If yes please read on.
The problem: The right answer (which just happens to be my answer in this case) for a very important question on this thread gets no justice and is being downvoted for appearance rather then content, while a very wrong answer is climbing up. The problem is that it will eventually contribute do the 'creation' and 'nurturing' of many bad developers if it stays the way it is (having a very wrong answer as an accepted top answer) as its nearly as important as the 'What is the base type for all .Net classes ?' question.
What you can do: If you feel any responsibility towards stackoverflow for all the hours of work it has saved you and you want to contribute to help create more quality developers rather then bad developers you can visit the thread(http://stackoverflow.com/questions/4240438/what-are-the-most-used-interfaces-in-c) and: 1)Upvote the question 2)downvote the highest answer 3) Give a few votes to my answer so at least its not perceived as wrong answer as its currently bellow 0 (was above but got downvoted by some people)
If you do that, you can go to bed today feeling good that you have contributed in a good meaningful way to a good cause, if not then thanks for looking anyway.