The ContentSerializerAttribute class is documented in the MSDN help. If you have specific questions about that documention, please ask them here: the more specific you can be about what you don't understand, the more likely that someone will be able to give you a useful answer.
If you have suggestions on how the documentation could be improved, please file them on the Connect site. The only way we know what needs to be improved is if people tell us about it, and again, the more specific you can be, the more likely that we will be able to act usefully on your suggestion.
I'm afraid I don't understand your second question.
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