For that type of net activity 3gb should be plenty. Your total net activity is measured when data is flowing in either direction. When you look at a web site you download the home page to your PC and that gets measured. If all you then do is look at that page but don't click on any links then nothing else gets measured. Similarly using MSN you only use your bandwidth when you send or receive a message. If you receive a message and then do nothing else but read it, no net activity takes place.
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Do you know that we're all in line for succession to the throne? Really?
Well, if forty-eight million, two hundred thousand, seven hundred and one people died I'd be Queen.