A blonde quickly went out to her mail box, looked in it, closed the door of the box, and went back in the house. 

A few minutes later she repeated this process by checking her mail again.

She did this five more times, and her neighbor that was watching her commented, "You must be expecting a very important letter today the way you keep looking into that mail box."

The blonde answered, "No, I am working on my computer, and it keeps telling me that I have mail."