At first see the questions below:
Here first question(Open Source Advertising - Sidebar - 1H 2010) is closed as exact duplicate of the second question (Open Source Advertising - Sidebar - 2H 2010). All contents of the first question is exactly copied to the second.
Now see the time of posting of both questions
So actual duplicate question will be second one (Open Source Advertising - Sidebar - 2H 2010). Then why first question is closed. I think it is very essential to view the time of posting while someone closing a question.